pro bel Freeway Manual page 37

Pro-Bel ltd
Technical manual
Pro-Bel General Switcher Communication Protocol
Pro-Bel General Switcher Communication Protocol is a robust, asynchronous
method of controlling routing switchers, It is the preferred method of controlling
Pro-Bel routers.
The normal electrical parameters of the interface are :
• RS485
• 8 bit data
• 1 stop bit
• EVEN parity
• 38.4K baud
Although the interface can be set to operate with any common RS485 and RS232
parameters.
The message format protocol is standard, and always conforms to the following
format :
SOM COMMAND MESSAGE CHECKSUM
Where :
SOM Start of message
=
FF Hex
COMMAND Command byte, which also defines message length
MESSAGE May be zero or more bytes
CHECKSUM
7 bit, 2s compliment sum of command and message field
(msb=O)
Pro-Bel General Remote Control Communication Protocol
This protocol has been developed to provide a common and robust method of
interfacing Pro-Bel control systems to a variety of standard and custom
applications. It is the standard protocol for interfacing a controller to a remote
device .
6540T-00 Nov 97
37