Gilderfluke&Co 16 Bit CD-Quality Digital Audio Systems - Manual (Page 71)

- AB/DR-3000 S ERIAL P ORT C OMMANDS -
The AB/DR-3000 can be controlled by simple switch closures to start and stop playback or looping,
mute the audio, and perform a variety of functions. Along with this method of controlling the AB/DR-
3000s, you can talk to as many as 255 AB/DR-3000s at one time through a serial data line from your
computer, terminal, or control system.
All commands sent to the AB/DR-3000 through its serial port take the following format. All characters
are in ASCII. All numeric values are in HEXadecimal (HEX for short) unless otherwise noted. They consist of
one or more ASCII characters (0-9, A through F). The case (as in upper and lower) of all input is impor-
tant. A lower case 'a' signifies a command, while an 'A' is a numeric value. If the AB/DR-3000 receives
another command while it is waiting for additional input needed to complete the previous command, it
will abandon the previous command and start working on the new one.
In the following documentation any input you will send to the audio system is shown in o u t l i n e . The
response to a command is shown in italics.
If the AB/DR-3000 is in a mode where you expect to receive some response from it (generally in one
of the echo modes), you must wait to receive all the characters you are expecting before sending the
system a new command. The reason for this is that you are actually talking to up to 256 microprocessors
at a time. If you issue a command that gives a response from one card, and then a command that
gives a response from a second card before the first has finished, the two may try to output data at the
same time. This won't cause any damage, but may result in garbled data at the receiver.
It is also possible to overload the AB/DR-3000 with too many commands through the serial port. You
don't want to take too much time away from the AB/DR-3000 to service the serial port.
To communicate with the AB/DR-3000 through the serial port, you can use just about any computer
or terminal that has a serial port on it. Some newer computer designs, like the Apple Macintosh, come
with serial ports that are directly compatible with the RS-422/RS-485 signal levels the AB/DR-3000 wants
to see. These signal levels are close enough to be used with the RS-232 signal levels found on most
older computers (like all IBM PCs and compatibles). They can be attached with only a simple adapter
cable, so long as the wire isn't too long and there arenÕt too many AB/DR-3000s attached to the same
serial line. To gain the full advantage of the RS-422/RS-485 signal levels (multidrop networking, distances
of up to a mile) you will need to use a signal level adapter.
If you are using a computer as a terminal you will need to run a modem or terminal emulation pro-
gram. ÔTERMINALÕ that comes with Windows will work just fine. Z-Term for Macintoshes is a shareware pro-
gram available for free or a nominal fee, as is BitCom for DOS. These will send everything you type on
the keyboard out the serial port on your computer while printing on the screen anything that comes in
from the audio system through the serial port.
A modem program will usually have the advantage over a terminal emulation program in that it will
allow you to save data to your computer's disk drives and restore it later. Unless VT-52 MODE is turned
ON, the AB/DR-3000 uses no screen control codes or <ESC>ape sequences, so it should work on any
machine with a 80 column by 24 line display. Machines with other display formats will work, but may not
look so neat on the screen.
When configuring your modem program, you should set it for 9600 baud, 8 data bits, one stop bit,
and no parity. You should set your program not to insert an extra LineFeed (LF) character after each
Carriage Return (CR) it receives, or else the menus will print Ôdouble spacedÕ. If you are going to be
downloading configuration strings to the system (command ÔsÕ), you will also need to tell the modem pro-
gram to put a slight delay between each character sent or use what is called ÔACK/NAKÕ handshaking.
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