User`s manual

SIERRA VIDEO
21
Communication
Protocol
Introduction
This section of this manual contains the most common Protocol commands. For a more
detailed list of Protocol commands contact the Sierra Video factory or go to
sierravideo.com/downloads.
The protocol uses the 7-bit ASCII character set, usually sent over an RS232-C or RS422
serial link — 9600 bps is recommended with 8 data bits and no parity. The protocol is
compact, with few characters required to cause switch changes to occur. It is also
human-readable and thus easy to understand and use. Several different crosspoint
switch request commands are defined, so that the one that is most compact for any given
switcher and application can be chosen.
The protocol is useful with both very small and very large routing switchers. The sizes of
the numbers representing inputs, outputs, and levels are not fixed, but can be as large or
small as necessary. Special provisions allow numbers to be packed one after another
with no intervening delimiter character, in order to make the protocol compact, as long as
each number is the largest size necessary for that particular switcher.
All input, output, and level numbers begin at number 1, not 0.
Note:
When writing commands for a “third party” controller, pay careful attention to the levels of control.
Chapter
4