RS232 Communication description for 2-channel recorders

Communication with Revox C27n and Studer A8O7, A810, A812, A816 and A820

Contents

  1. General communication description
  2. Additional notes on communication
  3. Command set tables
  4. Tape transport control commands
  5. Audio control commands
  6. Time code control commands
  7. Leader mode commands
  8. Machine commands
  9. Other commands
  10. List of known software updates

1. General communication description

Once you managed to get a RS-232 connection between computer and tape recorder working, you can start the communication from within your terminal program. The communication between the computer (controller) and the tape recorder is a master-slave protocol. The controller is the master and takes initiative in the communication. The controller sends commands to the recorder, the recorder will respond to these commands. Responses come in the form of information in your terminal screen (e.g. after command SD?, show software date) or in the form of an action (e.g. after command PLY the recorder will start playing).

The communication between the tape recorder and the computer is implemented through ASCII coded strings of variable length. A command is always composed of the following ASCII characters: The capital characters A thru Z, the question mark, a space, digits 0 thru 9. You can simply enter these characters in your terminal screen using your keyboard. Additionally, there are 5 special control characters:


    CR    - Character code 0D hex, a Carriage Return sign.
    LF    - Character code 0A hex, a Line Feed sign.
    CX    - Character code 18 hex, a reset sign (use Ctrl-x in a terminal)
    XOFF  - Character code 13 hex, meaning transmission off.
    XON   - Character code 11 hex, meaning transmission on.

When working with a terminal program you can send a CR sign by pressing the Enter key. In some terminal programs pressing Ctrl-m will work too. The recorder will mostly respond with signs CR and LF. In your terminal screen you will see the cursor move to the beginning of the next line, indicating it received a carriage return and a line feed.
Sign CX will reset the communication with the recorder to initial state. Depending on your terminal program, press Ctrl-x to send this sign (or an alternative from your terminal program).
Signs XON and XOFF are meant for software flow control to prevent communication going too fast causing overflows. Using a terminal program you will hardly ever need these signs. Modern computers are fast enough to handle incoming data from the recorder, and the recorder is fast enough to handle your typing speed. Should you feel inclined to prove otherwise, most terminal programs allow you to send XOFF by pressing Ctrl-s and XON by pressing Ctrl-q.

All commands have a length of max. 3 characters and are usually terminated by a ‘CR'. Commands with parameters will vary in length. The additional characters (parameters) are inserted between the command and ‘CR'. The parameters are separated by blanks or colons. There are a few exceptions: commands that do not have a terminating character. Please refer to the individual command description for the syntax of each command. The recorder uses the sequence 'CR LF' as an acknowledge message or to terminate an answer string.

An example of a command: WNF 0400 CR
In this example WNF is the command (for controlled wind forward) and 0400 is a parameter, indicating 4 times nominal speed. In your terminal screen you type WNF 0400 and press the Enter key to send the terminating CR sign.
The recorder answers with a CR LF sequence that moves the cursor in your terminal screen to the beginning of the next line, and it will start to wind forward at the chosen speed.

Not all commands listed below work with all recorders. If the recorder receives a command that it cannot handle it will respond with a question mark.
When using a terminal program, the recorders’ serial interface can operate in 'echo mode’. In this mode, a copy of each incoming character is echoed back to the controller/computer, and a prompt sign '>' is sent after the answer string. Echo mode on/off can be set via the recorder menu.

2. Additional notes on communication

3. Command set tables

The command set available for a particular tape deck depends on model, version and the software version of the tape deck. Whereas model and version will be known, the actual software version will be shown as a 4-digit number in the display of the tape recorder immediately after switching on. Number 4690 means it has the software version released in week 46 of year 1990. The software may have been updated in the course of the recorders lifetime.
Depending on your particular machine, commands listed may or may not be available to your machine. In the latter case you will receive an error message '?'. Additionally, your model may support commands not listed here. Some experimenting may prove useful.

Machine families are given as 3 letter codes:

Commands may have required and optional parts, as shown in the input and output columns. Required arguments are shown between square brackets, e.g. '[ ,CR]'. Optional arguments are shown between parenthesis like this: '( 0 <= xxxx <= 5FFFh )'.

Availability of a command is shown as a dash (not implemented) or an 'x' (implemented in at least one version of this machine family).

4. Tape transport control commands

Command  27n 807 810 812 820 816   Input                  Output             Meaning

STP       x   x   x   x   x   x    STP [ ,CR]             CR LF              Stop

EDI       x   -   -   x   x   x    EDI [ ,CR]             CR LF              Edit

PLY       x   x   x   x   x   x    PLY [ ,CR]             CR LF              Play

RPL       x   -   -   x   x   x    RPL [ ,CR]             CR LF              Reverse play

REC       x   x   x   x   x   x    REC [ ,CR]             CR LF              Record

FWD       x   x   x   x   x   x    FWD [ ,CR]             CR LF              Fast forward

RWD       x   x   x   x   x   x    RWD [ ,CR]             CR LF              Fast rewind

WNR speed -   x   -   x   x   -    WNR [ ] nnnn           CR LF              Controlled rewind
          -   -   -   -   -   x    WNR [ ] nnnn [ ,CR]    CR LF              0000 ≤ nnnn ≤ 5FFFh

WNF speed -   x   -   x   x   -    WNF [ ] nnnn           CR LF              Controlled fast forward
          -   -   -   -   -   x    WNF [ ] nnnn [ ,CR]    CR LF              0000 ≤ nnnn ≤ 5FFFh

TPL       -   -   x   -   -   -    TPL [ ,CR]             CR LF              Tape load

TPN       x   -   -   -   -   -    TPN [ ,CR]             CR LF              Tape dump on

TPF       x   -   -   -   -   -    TPF [ ,CR]             CR LF              Tape dump off

F         x   -   x   -   -   -    F [ ,CR]                                  Forward by synchronizer (needs ESY)

R         x   -   x   -   -   -    R [ ,CR]                                  Rewind by synchronizer (needs ESY)

SHS       x   -   x   -   -   -    SHS [ ,CR]             CR LF              Set high speed (2 speeds only)

SLS       x   -   x   -   -   -    SLS [ ,CR]             CR LF              Set low speed (2 speeds only)

SSA       -   x   -   x   x   x    SSA [ ,CR]             CR LF              Set play speed A (3.75 ips)

SSB       -   x   -   x   x   x    SSB [ ,CR]             CR LF              Set play speed B (7.50 ips)

SSC       -   x   -   x   x   x    SSC [ ,CR]             CR LF              Set play speed C (15 ips)

SSD       -   x   -   x   x   x    SSD [ ,CR]             CR LF              Set play speed D (30 ips)

SVP       -   -   -   x   x   x    SVP [ ] nnnnnn [ ,CR]  CR LF              Set varispeed parameter, refers to
                                                                             nominal play speed. Valid values
                                                                             are 00A5FE ≤ nnnnnn ≤ 018ACE
                                                                             Nominal fixed speed is 010000

NS?       x   -   -   -   -   -    NS? [ ,CR]             nn CR LF           Current play speed is?
                                                                             nn = 03-05 for 3.75-15 ips
          -   x   x   -   -   x    NS? [ ,CR]             nn CR LF           nn = 00-03 for 3.75-30 ips

          -   -   -   x   x   -    NS? [ ,CR]             nn IPS CR LF       nn = 3.75, 7.5, 15 or 30

VS?       -   -   -   x   x   x    VS? [ ,CR]             nnnnnn CR LF       Current varispeed is?
                                                                             Values 00A5FE ≤ nnnnnn ≤ 018ACE
                                                                             Nominal fixed speed is 010000

SVS       x   -   x   x   x   x    SVS [ ,CR]             CR LF              Set varispeed on

CVS       x   -   x   x   x   x    CVS [ ,CR]             CR LF              Set varispeed off

VEN       -   x   -   x   x   x    VEN [ ,CR]             CR LF              External varispeed on

VEF       -   x   -   x   x   x    VEF [ ,CR]             CR LF              External varispeed off

FEN       x   x   -   x   x   x    FEN [ ,CR]             CR LF              Enable fader

FEF       x   x   -   x   x   x    FEF [ ,CR]             CR LF              Disable fader

EDT       -   x   x   x   x   x    EDT [ ,CR]             CR LF              Lifter mode on, tape on heads

LFT       -   x   x   x   x   x    LFT [ ,CR]             CR LF              Lifter mode off, tape not on heads

LFN       -   x   x   x   x   x    LFT [ ,CR]             CR LF              Lifter mode on, audio muted;
                                                                             Corresponds lifter A

LOC addr  -   x   x   -   -   -    LOC (-)hh:mm:ss        CR LF              Locate to address hh:mm:ss
          x   -   -   -   -   -    LOC (-)hh:mm:ss CR     CR LF
          -   -   -   x   x   -    LOC (-)hh:mm:ss:nn     CR LF              nn = hundredths of seconds
          -   -   -   -   -   x    LOC (-)hh:mm:ss:n CR   CR LF              n = decimals

LMV addr  x   x   -   -   -   -    LMV xxxxxx CR          CR LF              Locate move roll (3 bytes hex)
          -   -   x   -   -   -    LMV xxxxxx             CR LF
          -   -   -   x   x   -    LMV xxxxxxxx           CR LF              Locate move roll (4 bytes hex)
          -   -   -   -   -   x    LMV xxxxxxxx CR        CR LF

ZLO       -   -   -   x   x   x    ZLO [ ,CR]             CR LF              Locate to zero

LZA       x   -   -   -   -   -    LZA [ ,CR]             CR LF              Locate to zero

LAD       x   -   -   -   -   -    LAD [ ,CR]             CR LF              Locate to address 1

LA?       x   -   -   -   -   -    LA? [ ,CR]            (-)hh:mm:ss CR LF   Locate address 1 is?

LOP       x   -   -   -   -   -    LOP [ ,CR]             CR LF              Auto loop 0000-loc 1 address

MV?       x   x   x   -   -   -    MV? [ ,CR]             xxxxxx CR LF       Move roll counter is?
          -   -   -   x   x   -    MV? [ ,CR]             xx xx xx CR LF
          -   -   -   -   -   x    MV? [ ,CR]             xxxxxxxx CR LF

STM addr  -   x   x   -   -   -    STM (-)hh:mm:ss        CR LF              Set timer to address
          x   -   -   -   -   -    STM (-)hh:mm:ss CR     CR LF
          -   -   -   x   x   -    STM (-)hh:mm:ss:d      CR LF
          -   -   -   -   -   x    STM (-)hh:mm:ss:d CR   CR LF

RTI       -   -   -   x   x   x    RTI [ ,CR]             CR LF              Reset timer

RTM       x   -   -   -   -   -    RTM [ ,CR]             CR LF              Reset timer

TRA       x   -   -   -   -   -    TRA [ ,CR]             CR LF              Copy timer to locate 1 address

SLA       x   -   -   -   -   -    SLA (-)hh:mm:ss CR     CR LF              Set locate 1 address to hh:mm:ss

TM?       x   x   x   -   -   -    TM? [ ,CR]             hh:mm:ss CR LF     Timer is?
          -   -   -   x   x   x    TM? [ ,CR]             hh:mm:ss:d CR LF

DST       -   x   x   -   -   -    DST [ ,CR]             CR LF              Enter status display mode
                                                          hh:mm:ss,x         (exit this mode with CX)
                                                          status..achieved
          -   -   -   x   x   x    DST [ ,CR]             CR LF              Enter status display mode
                                                           hh:mm:ss:x..nn    (exit this mode with CX)
                                                           status..achieved  nn = status of ST?

ST?       x   x   x   x   x   x    ST? [ ,CR]             nn CR LF           Tape deck status is?
          -   -   x   -   -   -                           00=tape out
          x   x   -   x   x   x                           01=tape out
          x   x   -   x   x   x                           81=tape out achieved
          -   -   x   -   -   -                           02=tape dump
          x   x   -   x   x   x                           02=stop
          -   -   x   -   -   -                           82=tape dump achieved
          x   x   -   x   x   x                           82=stop achieved
          x   x   x   x   x   x                           03=rewind
          x   x   x   x   x   x                           83=rewind achieved
          -   -   x   -   -   -                           04=stop
          x   x   -   x   x   x                           04=forward
          -   -   x   -   -   -                           84=stop achieved
          x   x   -   x   x   x                           84=forward achieved
          x   x   x   x   x   x                           05=play
          x   x   x   x   x   x                           85=play achieved
          -   -   x   -   -   -                           06=rewind achieved
          x   x   -   x   x   x                           86=play vari achieved
          -   -   -   x   x   -                           07=play int ref
          -   -   -   x   x   -                           87=play int ref achieved
          -   -   x   -   -   -                           08=forward
          x   x   -   x   x   x                           08=play ext ref
          -   -   x   -   -   -                           88=forward achieved
          x   x   -   x   x   x                           88=play ext ref achieved
          x   x   -   x   x   x                           09=rec or rehearse rec
          x   x   -   x   x   x                           89=rec/rehearse rec achieved
          -   -   x   -   -   -                           0A=play
          -   -   x   -   -   -                           8A=play achieved
          x   -   -   x   x   x                           0B=edit
          x   -   -   x   x   x                           8B=edit achieved
          -   -   x   -   -   -                           0C=record
          x   -   -   -   -   -                           0C=play fader
          -   -   x   -   -   -                           8C=record achieved
          x   -   -   -   -   -                           8C=play fader achieved
          -   -   x   -   -   -                           10=locate wind
          -   -   x   -   -   -                           12=locate play
          -   x   -   x   x   x                           25=reverse play
          -   x   -   x   x   x                           A5=reverse play achieved
          -   -   -   x   x   x                           26=reverse play vari
          -   -   -   x   x   x                           A6=reverse play vari achieved
          -   -   -   -   x   x                           27=rev play int ref
          -   -   -   -   x   x                           A7=rev play int ref achieved
          -   -   -   -   x   x                           28=rev play ext ref
          -   -   -   -   x   x                           A8=rev play ext ref achieved
          -   -   -   -   x   x                           29=rev rec or reh rev rec
          -   -   -   -   x   x                           A9=rev rec or reh rev rec achieved
          -   x   -   x   x   x                           40=shuttle reverse
          -   x   -   x   x   x                           C0=shuttle reverse achieved
          -   x   -   x   x   x                           41=shuttle forward
          -   x   -   x   x   x                           C1=shuttle forward achieved
          x   x   x   x   x   x                           42=locate rewind
          x   x   x   x   x   x                           C2=locate rewind achieved
          x   x   x   x   x   x                           43=locate forward
          x   x   x   x   x   x                           C3=locate forward achieved
          x   -   -   -   -   -                           45=locate play forward
          x   -   -   -   -   -                           C5=locate play forward achieved
          x   -   -   x   x   x                           46=cueing reverse
          x   -   -   x   x   x                           C6=cueing reverse achieved
          x   -   -   x   x   x                           47=cueing forward
          x   -   -   x   x   x                           C7=cueing forward achieved
          x   -   -   -   -   -                           48=position play reversed
          x   -   -   -   -   -                           C8=position play rev achieved
          -   x   x   x   x   x                           4A=rewind controlled
          -   x   x   x   x   x                           CA=rewind controlled achieved
          -   x   x   x   x   x                           4B=wind forward controlled
          -   x   x   x   x   x                           CB=wind forward controlled achieved
          -   -   -   -   -   x                           4C=rewind sht dev
          -   -   -   -   -   x                           CC=rewind sht dev achieved
          -   -   -   -   -   x                           4D=wind forward sht dev
          -   -   -   -   -   x                           CD=wind forward sht dev achieved
          x   x   x   x   x   x                           59=tape dump
          x   x   x   x   x   x                           D9=tape dump achieved
          -   -   -   x   x   x                           5A=cut
          -   -   -   x   x   x                           DA=cut achieved
          -   -   -   x   x   x                           DD=burn in achieved

LS?       x   -   -   -   -   -    LS? [ ,CR]             nn CR LF           Locator status is?
          x   -   -   -   -   -                           00=not locate
          x   -   -   -   -   -                           01=zero locate
          x   -   -   -   -   -                           02=address locate
          x   -   -   -   -   -                           03=search
          x   -   -   -   -   -                           04=auto loop
          x   -   -   -   -   -                           05=auto reverse
          x   -   -   -   -   -                           10=auto rewind
          x   -   -   -   -   -                           20=play preselected

PR?       -   -   x   -   -   -    PR? [ ,CR]             Y/N CR LF          Is pressure possible?

CS?       -   -   x   -   -   -    CS? [ ,CR]             Y/N CR LF          Is capstan in sync?

TP?       -   -   -   x   x   x    TP? [ ,CR]             aabbccddeeff       Tape tension parameter is?
                                                          gghhiijjkkll CR LF
                                                          tape width 1/4":
                                                          aa: tension play l
                                                          bb: tension play r
                                                          cc: tension wind
                                                          dd: tension edit
                                                          ee: tension rev play l
                                                          ff: tension rev play r
                                                          tape width 1/2":
                                                          gg: tension play l
                                                          hh: tension play r
                                                          ii: tension wind
                                                          jj: tension edit
                                                          kk: tension rev play l
                                                          ll: tension rev play r

DCD                                DCD [ ,CR]             CR LF              Display capstan deviation
          -   -   -   x   x   -                           nnnn               Deviation
          -   -   -   -   -   x                           CAP nnnn           8800h = nom. 9.525 cm/s
          -   -   -   -   -   x                                              9000h = nom. 19.05 cm/s
          -   -   -   -   -   x                                              A000h = nom. 38.1  cm/s
          -   -   -   -   -   x                                              C000h = nom. 76.2  cm/s
          -   -   -   x   x   -                                              0800h = nom. 3.75  ips
          -   -   -   x   x   -                                              1000h = nom. 7.5   ips
          -   -   -   x   x   -                                              2000h = nom. 15    ips
          -   -   -   x   x   -                                              4000h = nom. 30    ips
                                                                             Exit with CX

SP?       -   -   -   -   -   x    SP? [ ,CR]             xx CR LF           Number of splices?

DSN       -   -   -   -   -   x    DSN [ ,CR]             SPLICE yy:yy:yy:y  Display splice number
                                                          resp.              resp. takes at leader stop
                                                          TAKE xx yy:yy:yy:y xx = nr of splices resp.
                                                                             takes since leader stop
                                                                             updated after each event

DSF       -   -   -   -   -   x    DSF [ ,CR]             CR LF              Display of splice number 
                                                                             resp. nr of takes since stop

5. Audio control commands

Command  27n 807 810 812 820 816   Input                  Output             Meaning

SMN       -   -   x   x   x   x    SMN [ ,CR]             CR LF              Set mono (only with m/s switch)

SST       -   -   x   x   x   x    SST [ ,CR]             CR LF              Set stereo (only with m/s switch)

ION       -   x   -   -   -   -    ION [ ,CR]             CR LF              Insert on (set mono)

IOF       -   x   -   -   -   -    IOF [ ,CR]             CR LF              Insert off (set stereo)

SNB       -   x   x   x   x   x    SNB [ ,CR]             CR LF              Set NAB equalization

SCR       -   x   x   x   x   x    SCR [ ,CR]             CR LF              Set CCIR equalization

STA       -   x   -   x   x   x    STA [ ,CR]             CR LF              Set tape sort A

STB       -   x   -   x   x   x    STB [ ,CR]             CR LF              Set tape sort B

MSN       -   -   -   x   x   x    MSN [ ,CR]             CR LF              Master safe on

MSF       -   -   -   x   x   x    MSF [ ,CR]             CR LF              Master safe off

SRH       -   x   x   x   x   x    SRH [ ,CR]             CR LF              Rehearsal mode on
          -   -   -   x   x   x                                              only with dropin/out delay on

CRH       -   x   x   x   x   x    CRH [ ,CR]             CR LF              Rehearsal mode off

DDN       -   -   -   x   x   x    DDN [ ,CR]             CR LF              Drop in/out delay on

DDF       -   -   -   x   x   x    DDF [ ,CR]             CR LF              Drop in/out delay off

AA?       x   x   x   x   x   x    AA? [ ,CR]             aabbccdd CR LF     Channel 1..8 status is?
          x   x   x   x   x   x                           aa: 0 = safe
          x   x   x   x   x   x                               1 = ready/rec
          x   x   x   x   x   x                           bb: 0 = tape       MSB(xx) : channel 8
          x   x   x   x   x   x                               1 = input      LSB(xx) : channel 1
          x   x   x   x   x   x                           cc: 0 = rep
          x   x   x   x   x   x                               1 = sync
          -   x   x   x   x   x                           dd: 0 = demute     xx = aa .. dd
          -   x   x   x   x   x                               1 = mute
          x   -   -   -   -   -                           dd(h) = xxxxxxxx
          x   -   -   -   -   -                           xxxxxxxy           y: 0/1 = mic/line
          x   -   -   -   -   -                           xxxxxxyx           y: 0/1 = uncal/cal input
          x   -   -   -   -   -                           xxxxxyxx           y: 0/1 = uncal/cal output
          x   -   -   -   -   -                           xxxxyxxx           y: 0/1 = slow/fast
          x   -   -   -   -   -                           xxxyxxxx           y: 0/1 = varispeed off/on
          x   -   -   -   -   -                           xxyxxxxx           y: 0/1 = c_track off/on

REA i     x   x   x   x   x   x    REA i [ ,CR]           CR LF              Set channel i to ready
          -   -   x   -   -   -    i = 1,2,3
          -   -   -   x   x   -    i = 1,2,3,F                               E = tc channel
          x   -   -   -   -   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,E,F
          x   -   -   -   -   -    i = 1..8,F
          -   -   -   -   -   x    i = 1,2,E,F

SAF i     x   x   x   x   x   x    SAF i [ ,CR]           CR LF              Set channel i to safe
          -   -   x   -   -   -    i = 1,2,3
          -   -   -   x   x   -    i = 1,2,3,F                               E = tc channel
          x   -   -   -   -   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,E,F
          x   -   -   -   -   -    i = 1..8,F
          -   -   -   -   -   x    i = 1,2,E,F

INP i     x   x   x   x   x   x    INP i [ ,CR]           CR LF              Set channel i to input
          -   -   x   -   -   -    i = 1,2,3
          -   -   -   x   x   -    i = 1,2,3,F                               E = tc channel
          x   -   -   -   -   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,E,F
          -   -   -   -   -   x    i = 1,2,E,F
INP       x   -   -   -   -   -    INP [CR]               CR LF              Set all channels to input

SYN i     x   x   x   x   x   x    SYN i [ ,CR]           CR LF              Set channel i to synchronize
          -   -   x   -   -   -    i = 1,2,3
          -   -   -   x   x   -    i = 1,2,3,F                               E = tc channel
          x   -   -   -   -   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,E,F
          -   -   -   -   -   x    i = 1,2,E,F
SYN       x   -   -   -   -   -    SYN [CR]               CR LF              Set all channels to sync

REP i     x   x   x   x   x   x    REP i [ ,CR]           CR LF              Set channel i to reproduce
          -   -   x   -   -   -    i = 1,2,3
          -   -   -   x   x   -    i = 1,2,3,F                               E = tc channel
          x   -   -   -   -   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,E,F
          -   -   -   -   -   x    i = 1,2,E,F
REP       x   -   -   -   -   -    REP [CR]               CR LF              Set all channels to reproduce

MTN i     -   x   x   x   x   x    MTN i [ ,CR]           CR LF              Mute channel i
          -   -   x   -   -   -    i = 1,2                                   E = tc channel
          -   -   -   x   x   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,F
          -   -   -   -   -   x    i = 1,2,E,F

MTF i     -   x   x   x   x   x    MTF i [ ,CR]           CR LF              Channel i mute off
          -   -   x   -   -   -    i = 1,2                                   E = tc channel
          -   -   -   x   x   -    i = 1,2,F                                 F = all channels
          -   x   -   -   -   -    i = 1,2,3,4,F
          -   -   -   -   -   x    i = 1,2,E,F

MAN       -   -   x   -   -   -    MAN [ ,CR]           CR LF                Both channels mute on

MAF       -   -   x   -   -   -    MAN [ ,CR]           CR LF                Both channels mute off

MU?       -   -   -   x   x   x    MU? [ ,CR]           CR LF                Mute status is?
                                                                             b0/b1: 1 = mute on

SAP       -   x   x   x   x   x    SAP i,j,xx [ ,CR]    CR LF                Set audio parameter
  i,j,xx                           i=channel (1 or 2)                        Write in DAC's and store
                                   j=D/A converter:
          -   x   x   x   x   x    0=level repro/sync
          -   x   x   x   x   x    1=treble repro/sync
          -   -   x   x   x   x    2=bass repro/sync
          -   -   x   x   x   x    3=eq. repro/sync
          -   x   x   x   x   x    4=level record
          -   x   x   x   x   x    5=treble record
          -   x   x   x   x   x    6=bias record
          -   -   x   x   x   x    7=eq. record
          -   -   -   x   x   x    8=erase current level (MkII only)
          -   -   -   x   x   x    9=skimming bias level (MkII only)
                                   xx=hex value 00-FF

PAP       -   x   x   x   x   x    SAP i,j,xx [ ,CR]    CR LF                Preset audio parameter
  i,j,xx  -   x   x   x   x   x    SAP i,j [ ,CR]       CR LF                Cancel preset audio parm
                                   i=channel (1 or 2)                        Write in DAC's and store
                                   j=D/A converter:
          -   x   x   x   x   x    0=level repro/sync
          -   x   x   x   x   x    1=treble repro/sync
          -   -   x   x   x   x    2=bass repro/sync
          -   -   x   x   x   x    3=eq. repro/sync
          -   x   x   x   x   x    4=level record
          -   x   x   x   x   x    5=treble record
          -   x   x   x   x   x    6=bias record
          -   -   x   x   x   x    7=eq. record
          -   -   -   x   x   x    8=erase current level (MkII only)
          -   -   -   x   x   x    9=skimming bias level (MkII only)
                                   xx=hex value 00-FF

CAB speed -   -   -   x   x   x    CAB speed[ ,CR]      CR LF                Copy repro/sync parameter
                                   speed - 1..3                              tape sort A to B
                                   1=7.5, 2=15, 3=30ips

VAB speed -   -   -   x   x   x    VAB speed[ ,CR]      xx CR LF             Verify repro/sync parameter
                                   speed - 1..3                              compare tape sort A to B
                                   1=7.5, 2=15, 3=30ips                      xx: 00=failed, 01=success

AP? i,j   -   x   x   x   x   x    AP? i,j[ ,CR]        xx CR LF             Audio parameter is?
                                   i=channel (1 or 2)
                                   j=D/A converter:
          -   x   x   x   x   x    0=level repro/sync
          -   x   x   x   x   x    1=treble repro/sync
          -   -   x   x   x   x    2=bass repro/sync
          -   -   x   x   x   x    3=eq. repro/sync
          -   x   x   x   x   x    4=level record
          -   x   x   x   x   x    5=treble record
          -   x   x   x   x   x    6=bias record
          -   -   x   x   x   x    7=eq. record
          -   -   -   x   x   x    8=erase current level (MkII only)
          -   -   -   x   x   x    9=skimming bias level (MkII only)
                                   xx=hex value 00-FF

TS?       -   -   -   x   x   x    TS? [ ,CR]           xx CR LF             Tape sort is?
                                                        xx=00 for tape A
                                                        xx=01 for tape B

EQ?       -   -   -   x   x   x    EQ? [ ,CR]           xx CR LF             Equalization norm is?
                                                        xx=00 for CCIR
                                                        xx=01 for NAB

MIC       x   -   -   -   -   -    MIC [ ,CR]           CR LF                Set mic on

LIN       x   -   -   -   -   -    LIN [ ,CR]           CR LF                Set line on

CON       x   -   -   -   -   -    CON [ ,CR]           CR LF                Set calibrate output on

COF       x   -   -   -   -   -    COF [ ,CR]           CR LF                Set calibrate output off

CIN       x   -   -   -   -   -    CON [ ,CR]           CR LF                Set calibrate input on

CIF       x   -   -   -   -   -    COF [ ,CR]           CR LF                Set calibrate input off

CC?       -   -   -   x   x   x    CC? [ ,CR]           aa CR LF             Channel configuration is?
                                                                             aa=no. of channels in hex

6. Time code control commands

Command  27n 807 810 812 820 816   Input                  Output             Meaning

STD yy    x   -   -   -   -   -    STD yy[ ,CR]           CR LF              Set time code data
                                   y: C=real time
                                      T=clock time
                                      D=date
                                      K=code
                                      -=nothing
                                   yy=CC                                     Record real time counter
                                   yy=TT                                     Record clock time
                                   yy=DD                                     Record date
                                   yy=KK                                     Record code
                                   yy=CT                                     Record real time + clock time
                                   yy=CC                                     Record clock time + real time

CD?       x   -   -   -   -   -    CD? [ ,CR]             y (-)d (y (-)d) CR Read corrected data from tape
                                                          y: C=real time
                                                             T=clock time
                                                             D=date
                                                             K=code

                                                          d: hh:mm:ss counter,time
                                                             DD:MM:YY date
                                                             xxxxxx code

                                                          C (-)hh:mm:ss CRLF Real time counter on tape
                                                          D DD.MM.YY T hh:mm:ss CR LF  Date + clock time on tape
                                                          K xxxxxx CR LF     Code on tape
                                                          - CR LF            No data on tape

UD?       x   -   -   -   -   -    UD? [ ,CR]             y (-)d (y (-)d) CR Read uncorrected data from tape
                                                          y: C=real time
                                                             T=clock time
                                                             D=date
                                                             K=code

                                                          d: hh:mm:ss counter,time
                                                             DD:MM:YY date
                                                             xxxxxx code

                                                          C (-)hh:mm:ss CRLF Real time counter on tape
                                                          D DD.MM.YY T hh:mm:ss CR LF  Date + clock time on tape
                                                          K xxxxxx CR LF     Code on tape
                                                          - CR LF            No data on tape

ER?       x   -   -   -   -   -    ER? [ ,CR]             xxxxxx yyyy CR LF  Recording errors?
                                                                             xxxxxx=No. of recorded data sets
                                                                             yyyy=Total number of errors

TD?       x   -   -   -   -   -    TD? [ ,CR]             y (-)d (y (-)d) CR Selected time code data?
                                                          y: C=real time
                                                             T=clock time
                                                             D=date
                                                             K=code

                                                          d: hh:mm:ss counter,time
                                                             DD:MM:YY date
                                                             xxxxxx code

                                                          C (-)hh:mm:ss CRLF Real time counter selected
                                                          D DD.MM.YY T hh:mm:ss CR LF  Date + clock time selected
                                                          K xxxxxx CR LF     Code selected
                                                          - CR LF            No selected data

SAC       x   -   -   -   -   -    SAC [ ,CR]             CR LF              Set search algorithm for recording

SAL       x   -   -   -   -   -    SAL [ ,CR]             CR LF              Set search algorithm for logging apps

JCL time  x   -   -   -   -   -    JCL hh:mm:ss[ ,CR]     CR LF              Search clock time

JCM addr  x   -   -   -   -   -    JCM hh:mm:ss[ ,CR]     CR LF              Search real time counter

JCD addr  x   -   -   -   -   -    JCD hh:mm:ss[ ,CR]     CR LF              Search clock time and date

JTD addr  x   -   -   -   -   -    JTD hh:mm:ss[ ,CR]     CR LF              Search real time counter and date

TDN       -   -   x   x   x   -    TDN [ ,CR]             CR LF              Time code delay on, left+right active

TDF       -   -   x   x   x   -    TDF [ ,CR]             CR LF              Time code delay off, right TC active

TH?       -   -   x   x   x   x    TH? [ ,CR]             xx CR LF           Time code reading head no. is?

TC?       x   x   x   x   x   x    TH? [ ,CR]             [Y,N] CR LF        Is time code present on tape?

TCN       -   x   -   -   -   -    TCN [ ,CR]             CR LF              Set time code delay active

TCF       -   x   -   -   -   -    TCF [ ,CR]             CR LF              Set time code delay bypassed

TV?       x   -   -   -   -   -    TV? [ ,CR]             [Y,N] CR LF        Verify time code

SCO code  x   -   -   -   -   -    SCO xxxxxx [ ,CR]      CR LF              Set code at xxxxxx

CO?       x   -   -   -   -   -    CO? [ ,CR]             xxxxxx CR LF       Code is?

CTN       x   -   -   -   -   -    CTN [ ,CR]             CR LF              c_track on

CTF       x   -   -   -   -   -    CTF [ ,CR]             CR LF              c_track off

TO?       -   -   -   -   -   x    TO? [ ,CR]             [Y,N] CR LF        Time code option is?

SCK time  x   -   x   -   -   -    SCK hh:mm:ss [ ,CR]    CR LF              Set clock at hh:mm:ss

CL?       x   -   x   -   -   -    CL? [ ,CR]             CR LF              Clock is?

7. Leader mode commands

Command  27n 807 810 812 820 816   Input                  Output             Meaning

LOF       -   -   -   -   -   x    LOF xx[ ,CR]           CR LF              Set leader offset (00-FF hex)

LO?       -   -   -   -   -   x    LO? [ ,CR]             xx CR LF           Leader offset is? (00-FF hex)

CAY       -   -   -   -   -   x    CAY [ ,CR]             CR LF              Calibrate tape colour

YT?       -   -   -   -   -   x    YT? [ ,CR]             xx CR LF           Tape colour is?
                                                                             xx: 0/1 = magnetic/blank

SCP       -   -   -   -   -   x    SCP [ ,CR]             CR LF              Start control on (play)

SCL       -   -   -   -   -   x    SCL [ ,CR]             CR LF              Start control off (locate)

SC?       -   -   -   -   -   x    SC? [ ,CR]             xx CR LF           Start control?
                                                                             xx: 0/1 = inactive/active

LEN       -   -   -   -   -   x    LEN [ ,CR]             CR LF              Set leader mode on

LEF       -   -   -   -   -   x    LEF [ ,CR]             CR LF              Set leader mode off

LE?       -   -   -   -   -   x    LE? [ ,CR]             xx CR LF           Leader mode is?
                                                                             xx: 0/1 = off/on

VLN       -   -   -   -   -   x    VLN [ ,CR]             CR LF              Vertical lifter on

VLF       -   -   -   -   -   x    VLF [ ,CR]             CR LF              Vertical lifter off

VL?       -   -   -   -   -   x    VL? [ ,CR]             xx CR LF           Vertical lifter is?
                                                                             xx: 0/1 = inactive/active

8. Machine mode commands

Command  27n 807 810 812 820 816   Input                  Output             Meaning

LCD       x   x   x   x   x   x    LCD [ ,CR]             CR LF              Local keyboard disabled

LCE       x   x   x   x   x   x    LCE [ ,CR]             CR LF              Local keyboard enabled

RMD       x   -   -   x   x   x    RMD [ ,CR]             CR LF              Remote keyboard disabled

RME       x   -   -   x   x   x    RME [ ,CR]             CR LF              Remote keyboard enabled

CFA       -   -   -   -   -   x    CFA [ ,CR]             CR LF              Set standard key configuration

CFB       -   -   -   -   -   x    CFB [ ,CR]             CR LF              Set broadcast key configuration

CF?       -   -   -   -   -   x    CF? [ ,CR]             aa CR LF           Current key configuration is?
                                                                             aa: 0/1=standard/broadcast config

SPA       -   -   -   x   x   x    SPA [ ,CR]             CR LF              Save au+td parameters (recommended way to save all settings)

LPA       -   -   -   x   x   x    LPA [ ,CR]             CR LF              Load au+td parameters (recommended way to restore all settings)

SCF       -   -   -   x   x   x    SPA [ ,CR]             CR LF              Save key configuration

LCF       -   -   -   x   x   x    LPA [ ,CR]             CR LF              Load key configuration

SMD       -   -   -   -   -   x    SMD [ ,CR]             CR LF              Save function modes + addresses

LMD       -   -   -   -   -   x    LMD [ ,CR]             CR LF              Load function modes + addresses

QSL       -   -   -   x   x   x    QSL [ ,CR]             CR LF              Quit save/load process; if SL? state 
                                                                             is 1, 2 or 4 this command is lost

SL?       -   -   -   x   x   x    SL? [ ,CR]             xx CR LF           Process state on save/load config is?
                                                          xx:00h=no process
                                                             01h=saving
                                                             02h=loading
                                                             03h=verifying
                                                             04h=saving done
                                                             05h=loading done
                                                             06h=verifying done
                                                             07h=saving failed
                                                             08h=loading failed
                                                             09h=verifying failed
                                                             0Ah=loading awaited
                                                             0Bh=verifying awaited
                                                             0Ch=no data found
                                                             0Dh=wrong data set load
                                                             0Eh=wrong data set verify

SMA       -   -   x   -   -   -    SMA nnnnnn [ ,CR]      CR LF              Set machine serial number

MA?       -   -   x   -   -   -    MA? [ ,CR]             nnnnnn CR LF       Machine serial number is?

SBA addr  -   -   -   x   x   x    SBA xxxx[ ,CR]         CR LF              Set bus address (8280-FFFF)

BA?       -   -   -   x   x   x    BA? [ ,CR]             xxxx CR LF         Bus address is? (8280-FFFF)

SDN       x   -   -   -   -   -    SDN xx [ ,CR]          CR LF              Set device number

DN?       x   -   -   -   -   -    SDN [ ,CR]             xx CR LF           Device number is?

SD?       x   x   x   x   x   x    SD? [ ,CR]             DD.MM.YY           Software date is?
                                                          00.WW.YY           DD.MM.YY = sw not released
                                                                             00.WW.YY = week/year sw released

SDA date  x   -   -   -   -   -    SDA DD.MM.YY[ ,CR]     CR LF              Set date to DD.MM.YY

DA?       x   -   -   -   -   -    DA? [ ,CR]             DD.MM.YY CR LF     Current date is?

MK?       -   -   -   x   x   x    MK? [ ,CR]             aa CR LF           Mark no. of software is?
                                                                             aa: 00,01,? = mark I
                                                                             aa: 02 = mark II

MT?       -   x   x   x   x   x    MT? [ ,CR]             aa CR LF           Machine type is?
                                                                             aa: 01=A820, 02=A812, 
                                                                                 03=A820MCH, 04=A827MCH,
                                                                                 05=A807, 06=A816, 07=A810
          x   -   -   -   -   -    MT? [ ,CR]             aaaa CR LF         C270, C274 or C278

ESY       x   x   x   -   -   -    ESY [ ,CR]             CR LF              Enable synchronizer

DSY       x   x   x   -   -   -    DSY [ ,CR]             CR LF              Disable synchronizer

9. Other commands

The microprocessor and peripherals that control your tape recorder are from Motorola's A6800 family of microprocessor chips. Some of the commands and formats known from this Motorola CPU-family made their way to the tape recorders. Especially the A810 supports a number of these commands, but other models and/or software versions seem to support some of these as well.
These commands allow you to access the recorders RAM and therefore can be used for backing up, restoring and documenting audio settings.


Command       Input                Output                 Meaning

D (display)   D start end CR       Formatted hex dump     Display RAM content from start adress (hex)
                                                          to end address (hex). See example below.

P (punch)     P start end CR       Exorcisor format dump  Write RAM content starting at (address in hex)
                                                          to end address (in hex) in Motorola Exorcisor 
                                                          format to the terminal. See example below.

L (load)      L data CR            CR LF                  Load RAM-data in Exorcisor format to recorder.

S (save)      S CR                 data CR LF             Save RAM-data in Exorcisor format to computer.

UAP           UAP addr value CR    CR LF                  Update audio parameter at hex address with
                                                          hex value.

Commands D and P can be used to access the content of RAM. The parameter range, where all settings are stored, starts at decimal address 264 (108 in hex). So for both D and P the starting address should be 108. The end address must be given in hexadecimal. In order to access the full parameter range it should be at least 26F. With an A810 connected sending command D 108 26F CR produces this output:


      0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F  
0100 01 00 02 60 FF FE BF FF 82 70 90 AB 26 90 30 BB  ...`..?....+x.0;
0110 00 00 00 00 66 39 80 87 30 A0 3E 75 62 50 96 87  .....9..0 ...P..
0120 66 39 80 6D 30 9A 2A B1 62 A0 96 61 66 30 6A 44  .9..0.*1. ...0.D
0130 30 54 46 BA 62 50 88 44 66 30 6A 61 30 39 46 E0  0TF:.P.D.0..09F`
0140 62 A0 88 61 66 38 48 26 30 1B 50 DE 62 50 60 26  . ...8Hx0.P^.P`&
0150 82 70 90 AB 26 90 30 BB 00 00 00 00 66 39 80 87  ...+&.0;.....9..
0160 30 A0 3E 75 62 50 96 87 66 39 80 6D 30 9A 2A B1  0 ...P...9..0.*1
0170 62 A0 96 61 66 30 6A 44 30 54 46 BA 62 50 88 44  . ...0.D0TF:.P.D
0180 66 30 6A 61 30 39 46 E0 62 A0 88 61 66 38 48 26  .0..09F`. ...8Hx
0190 30 1B 50 DE 62 50 60 26 82 70 90 AB 26 90 30 BB  0.P^.P`x...+x.0;
01A0 00 00 00 00 66 39 80 87 30 A0 3E 75 62 50 96 87  .....9..0 *..P..
01B0 66 39 80 6D 30 9A 2A B1 62 A0 96 61 66 30 6A 44  .9..0.*1. ...0.D
01C0 30 54 46 BA 62 50 88 44 66 30 6A 61 30 39 46 E0  0TF:.P.D.0..09F`
01D0 62 A0 88 61 66 38 48 26 30 1B 50 DE 62 50 60 26  . ...8Hx0.P^.P`&
01E0 82 70 90 AB 26 90 30 BB 00 00 00 00 66 39 80 87  ...+&.0;.....9..
01F0 30 A0 3E 75 62 50 96 87 66 39 80 6D 30 9A 2A B1  0 ...P...9..0.*1

      0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F  
0200 62 A0 96 61 66 30 6A 44 30 54 46 BA 62 50 88 44  . ...0.D0TF:.P.D
0210 66 30 6A 61 30 39 46 E0 62 A0 88 61 66 38 48 26  .0..09F`. ...8Hx
0220 30 1B 50 DE 62 50 60 26 49 00 00 00 00 00 00 00  0.P^.P`xI.......
0230 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0240 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0250 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
0260 00 00 00 00 00 00 00 00 00 00 00 00 00 94 7E 00  ................

This is a hexadecimal dump of the RAM-area that contains all audio settings. Each setting (parameter) occupies one byte, hence has a value between 00h and FFh (between 0 and 255 in decimal). Addresses of audio parameters can be calculated using this formula:


RADR  = ARAM-12 + IDAC + ISYNC*8 + CCAB*12 + SPEED*24 + CHNL*72 + TAPE*144

RADR  = Relative address in decimal, an offset from absolute address 108 hex.
ARAM  = Absolute addres in RAM (in hex 108, in decimal 264).
IDAC  = 0 for level repro,  1 for treble repro,  2 for bass repro,  3 for equalization repro,
        4 for level record, 5 for treble record, 6 for bias record, 7 for equalization record,
        8 for erase current level, 9 for skimming bias level (8 and 9 for A820 only)
ISYNC = 0 for repro mode, 1 for sync mode.
CCAB  = Equalization, 0 for CCIR, 1 for NAB (at 3.75 ips always NAB, at 30 ips always CCIR).
SPEED = 0 for 3.75 ips, 1 for 7.5 ips, 2 for 15 ips, 3 for 30 ips.
CHNL  = 0 for channel 1, 1 for channel 2.
TAPE  = 0 for tape sort A, 1 for tape sort B (A810: 1 for A, 0 for B).

With an A810 connected sending command P 108 26F CR produces this output:


S0* A810 *
S11B0108827090AB269030BB000000006639808730A03E756250968715
S11B01206639806D309A2AB162A0966166306A44305446BA6250884453
S11B013866306A61303946E062A0886166384826301B50DE6250602613
S11B0150827090AB269030BB000000006639808730A03E7562509687CD
S11B01686639806D309A2AB162A0966166306A44305446BA625088440B
S11B018066306A61303946E062A0886166384826301B50DE62506026CB
S11B0198827090AB269030BB000000006639808730A03E756250968785
S11B01B06639806D309A2AB162A0966166306A44305446BA62508844C3
S11B01C866306A61303946E062A0886166384826301B50DE6250602683
S11B01E0827090AB269030BB000000006639808730A03E75625096873D
S11B01F86639806D309A2AB162A0966166306A44305446BA625088447B
S11B021066306A61303946E062A0886166384826301B50DE625060263A
S11B022849000000000000000000000000000000000000000000000071
S11B0240000000000000000000000000000000000000000000000000A2
S11B0258000000000000000000000000000000000000000000947E0078
S9030000FC

This is a dump of all the parameter values in the requested RAM-area in Exorcisor format. This format is useful for load and save operations of the RAM-area that contains the audio setting parameters, because Exorcisor format contains checksums per record.

See Wikipedia for a description of Exorcisor format.

10. List of known machine software updates


02.06.1986:  EDT,LFT implemented for A812 and A820
13.06.1986:  error message for A812 and A820:
             CR LF "?" CR LF replaced by "?" CR LF
             CR LF "INPUT FORMAT ERROR" CR LF replaced by "INPUT FORMAT ERROR" CR LF
18.07.1986:  In part: "commands for internal use only" got commands
             "B" break disabled
             "L" load disabled
             "V" verify disabled
13.08.1986:  EDI disabled for A812 and A807 new implemented
02.09.1986:  EMC & DMC disabled for A812 and A820
             PAP new implemented for A812 and A820
15.01.1987:  TC? new implemented for A812 and A820
17.09.1987:  AA? new implemented for A812 and A820
21.10.1987:  TDF & TDN commentary accomplished
03.11.1987:  ION,IOF implemented for A807
04.11.1987:  SD? implemented for all machines
09.11.1987:  MIC,LIN,CON,COF implemented for C270
09.11.1987:  CIF,CIN,SDN,DN? implemented for C270,C274,C278
11.11.1987:  LAD, LA?, LOP, TPN, TPF implemented for C270, C274, C278
03.12.1987:  RPL, SDA, DA?, SC0, CO?, CTN, CTF, STD, TD?, CD?, UD?, SAC, SAL, 
             JTM and JCL implemented for C274, C278
14.12.1987:  ER?, DSY implemented for C274, C278
16.12.1987:  ZLO and RTI implemented for A812 and A820
18.12.1987:  LZA implemented for C270, C274, C278
09.02.1988:  RTM, TRA, MT? implemented for C274, C278
10.02.1988:  RTM, TRA, MT? implemented for C270
16.02.1988:  Locator status ‘autoreverse’ implemented for C274, C278
16.02.1988:  Status ‘locator play reverse’ implemented for C274, C278
16.02.1988:  Status ‘locator play reverse achieved’ implemented for C274, C278
14.03.1988:  LS?: additional preselected play implemented for C270, C274, C278
23.03.1988:  JCD, JTD implemented for C274L, C278L
13.01.1989:  TP? new implemented for A812 and A820
17.01.1989:  MK? new implemented for A812 and A820
17.01.1989:  SAP, PAP, AP? completed with selector values 8 and 9 for erase
             current level and skimming current level (only MK II models)
18.01.1989:  MT? new implemented for A812 and A820
06.06.1989:  TCN, TCP implemented for A807
21.06.1989:  Status RPL (reverse play) redefined from OAh/8Ah to 25h/OA5h; 
             Status RPV (rev play varispeed), RPI (rev play vspd int ref) and 
             RPE (rev play vspd ext ref) new for A812 and A820
09.08.1989:  A807 audio commands completed for tc channel. 
             Command RPL implemented for A820 and A812
03.11.1989:  Command TP? doesn’t print tape tension reverse play left/right on A812
06.12.1989:  SVS, CVS, VS? and SVP new implemented for A820/A812 MkII
11.12.1989:  LOC and STM corrected for A807: no CR LF at end
14.02.1990:  A816: CR consequently for all commands, CC? and TO? new for A816
16.02.1990:  General remarks to control x, xon, xoff protocol
24.09.1990:  MT? new implemented for A810
04.04.1991:  PAP without parameter now means "cancel preset audio parameter"
27.07.1992:  STM description for A820, A812, A816 corrected (dms: from xxx to x)
27.08.1992:  LOC description for A820, A812, A816 corrected (dms: from xxx to x)
19.10.1992:  CFA, CFB and CF? for A816 for setting/requesting broadcast mode introduced
20.10.1992:  SPA, LPA, SCF, LCF, SL?, QSL for A816 for saving au+td parameters, loading 
             au+td parameters, saving keys, loading keys, requesting process state and 
             quitting process introduced
02.11.1992:  TDF & TDN disabled for A816 (no TC version 1)
03.11.1992:  SMD, LMD for A816 for saving & loading function modes and addresses introduced
23.12.1992:  ST? completed for A816 with states 4C/4D = wind with shuttle deviation
03.03.1993:  For A816 error messages "SWITCH EDIT LEVER TO NORMAL POSITION, PLEASE !™ and
             "OVERRUN FRAMING ERROR !" at echo mode introduced
10.03.1994:  SL? has more states to be displayed: also ODh and OEh possible
24.03.1994:  MU? to display channel mute state implemented for A816
27.01.1995:  CC?, MU? to display ch conf & ch mute states implemented for A812/A820
14.02.1995:  SPA, LPA, SL?, QSL introduced for A812MkII and A820MkII
21.03.1995:  CAB, VAB introduced for A812MkII, A820MkII and A816
25.09.1996:  LOF, LO? ,CAY, YT?, SCP, SCL, SC?, LEN, LEF, LE?, VLN, VLF,VL? for A816
10.10.1996:  LCF and SCF for A820 2channel and A812
28.02.1997:  TS? (tape sort A or B) and EQ? (ccir or nab) for A816, A812, A820
04.04.1997:  DCD (display capstan deviation) for A816, A812, A820
04.04.1997:  DSN/DSF (display splice nr/takes on/off) for A816
01.05.1997:  DSN for A816 corrected: shows address also
22.05.1997:  DSN at A816: max. splice length = 104.16mm (filter); SP? for AB16
30.07.1997:  DCD response with ‘CAP ' string only for A816