Contemporary Research IP-232 Ethernet to RS-232 Interface - Manual (Page 7)

RS-232/IP Control Protocol
Overview
The IP-232’s full duplex RS-232 and Telnet protocol enables a system programmer to set up RS-232 port
operation and IP addressing. All commands are sent as ASCII strings. No delays between characters or
commands are required, as data is interrupt driven and buffered. The same RS-232 protocol can be sent
over IP, sent to Telnet port 2728.
All settings are saved to NVRAM in the IP-232.
General protocol specifications
Characters in command strings to the IP-232 are common ASCII keyboard characters.
Command strings sent to the IP-232 begin 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 IP-232 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 0-9 when used in multiple tuner applications.
To address all units, use a Unit # of 0 (Zero)
No unit number will default to 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.
Command and Status Response
Commands can be sent back to back at any time without any delay. To allow for rapid, multiple commands,
status responses are intentionally delayed by about 125mS, sending the most current status in response to
control commands or user actions.