Sierra Video Sequoia Family - Manual (Page 37)

SIERRA VIDEO SYSTEMS
31
Communication
Protocol
Introduction
The protocol uses the 7-bit ASCII character set, usually sent over an RS232-C or RS422 serial
link — 115.2K Baud 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 5