Gilderfluke&Co Frequency Shift Keyed/Remote Terminal Unit - Manual (Page 26)

- SONY LaserDisk COMMANDS -
The Sony LaserDisk players all share a more or less common command format. A full description of the
commands can be found in the technical publications available from Sony or your Sony dealer. You
should confirm the the usage of these commands for the specific player you are using.
LaserDisks used with the FSK/RTU may be recorded in the CAV or CLV format. This allows up to 1 hour
per side. The FSK data must be recorded on one of the audio tracks much as they would be on any audio
tape FSK installation. The gaps in the FSK data between shows is used by the FSK/RTU to recognize the ends
of shows and decide when to send each of the strings.
The LaserDisk player must be configured for 9600 baud, 8 bit data, and 1 stop bit. Connections are
made as follows:
Sony LaserDisk
DB-25 SIGNAL SIGNAL FROM/TO FSK/RTU
2 DATA OUT - serial data in to FSK/RTU (GREEN)
3 DATA IN - serial data out from FSK/RTU (BLACK)
7 GROUND signal ground (BLUE or WHITE)
4 to 5 RTS/CTS connect these two lines
6 to 20 DSR/DTR connect these two lines
The electrical output from PC•MACs is at RS-422 voltage levels rather than the RS-232 that these
LaserDisk players really want to see. If this causes a problem, or it the wire runs between PC•MACs and the
LaserDisk player are long, then you may want to add a RS-232 to RS-422 converter to the LaserDisk player.
In general, you send a command to the LaserDisk player as a single ASCII character. The LaserDisk
player will then respond that it has received the command with a ‘ACK’ (0A). When it has completed the
task it will sometimes respond with a ‘COMPLETION CODE’ (01 usually). Each command must be transmit-
ted one at a time, after which you must wait for a return code(s) before you can send any additional
commands.
The majority of commands which you might need to use are all pretty simple ones. The one compli-
cated ‘search’ command is handled transparently to you when you insert a LaserSearch (01) character in
the string being sent to the LaserDisk player (the FSK/RTU must be told it is running a Sony player in the
configuration screen). This string only performs a search for the starting frame of the show on the LaserDisk
player. For this reason it is normally followed by a ‘F-PLAY’ (3A) command in the same string.
A typical start string for a LaserDisk show is:
‘F-PLAY’ <ACK> end-o-string
Translated into HEX ASCII, this string becomes (this is what you would enter):
3A 8A 00
Notice that we have to then tell the LaserDisk to start playing, and then we tell the FSK/RTU to wait until
it gets an ‘ACK’ (0A) back from the LaserDisk player so we know that the command has been accepted.
After this we have a ‘00’ to tell the FSK/RTU that it has found the end of the string.
A typical end string for a Sony LaserDisk show is:
‘STILL’ <ACK> end-o-string
Translated into HEX ASCII, this string becomes (this is what you would enter):
4F 8A 00
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