Network Router User Manual

Contemporary Research Corporation 7 AV6x4 A/V Router
RS-232 Control Protocol
Overview
The AV6x4 full-duplex RS-232 scheme enables a system programmer to control all routing functions as well as
monitor 3 groups of unit status. All commands are sent as ASCII strings. No delays between characters or
commands are required, as data is interrupt driven and buffered.
There are three types of commands and responses—Crosspoint, Input Gain and Front Panel. Crosspoint
commands route Input 1-6 audio and video to Outputs 1-4. Audio Gain commands adjust the audio gain of
each input between -9 to +9 dB, allowing the user to balance levels for all inputs. Front Panel commands
provide several front-panel mode and lockout functions. A corresponding Crosspoint, Input Gain or Front Panel
ASCII response will be sent when a valid command has been received. In addition, all three status strings will
be sent on power-up or by and RS-232 status request at any time.
Up to 3 AV6x4s, or a combination of three Contemporary 232-series components, may be cabled together and
addressed for individual control from a single RS-232 port. Each unit is assigned a unique unit code (Front Panel
Mode 2). All settings are saved to NVRAM.
Communications parameters (Front Panel Mode 1) are 300 to 9600 baud, 8 data bits, No parity, and 1 stop bit.
Factory default is 9600 baud, Unit#1.
General protocol specifications
Characters in command strings to the AV6x4 are common ASCII keyboard characters.
Command strings sent to the AV6x4begin with the ASCII > (greater than symbol) as an 'Attention' character
and end with carriage return - ASCII CR, Hex $0D, or keyboard Enter - as an 'End-of-command' character.
Responses from the AV6x4 begin with the ASCII < (less than symbol) as an 'Attention' character and end with a
carriage return followed by line feed an ASCII LF or Hex $0A as 'End-of-command' characters.
A carriage return is required at the end of each command and is assumed in all examples
.
Command String Structure
[Attention] (Unit#) [Command] (Parameters) [Return]
Attention Single character (>) starts the string
Unit# The Unit# is expressed as an ASCII 1 2 or 3 when used in multi AV6x4applications.
It may be omitted for a default of Unit#1 for a single AV6x4set as Unit#1.
Command A two-character command
Parameters Added attributes to some commands
Return A carriage return ends the command string, you may use ASCII CR, Hex $0D, or keyboard
‘Enter’ in programming. For simplicity, the programming examples in the manual will not show
the ‘CR’ – so remember, you’ll need to add it in your control code.