Sierra Video Manzanita 321V - Manual (Page 9)

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INSTRUCTION MANUAL
9
Command string
Commands are sent to a routing switcher in a
group called a command string. A command
string can contain zero or more commands,
limited only by the size of the receive buffer of
the switcher, which should be large enough to
hold a command string for setting the state of the
entire switcher matrix.
A command string consists of a leader, zero or
more commands, and a trailer. If a leader character
is encountered within the command string, the
command string up to that point is discarded and a
new command string is started. Once a complete
command string, up to the trailer character, is
received, the routing switcher executes the
commands within it.
Within the command string, certain ASCII charac-
ters may be present and are ignored: any ASCII
character whose code is less than or equal to the
SPACE character, and any whose code is greater
than the “~” (tilde) character. Alphabetic charac-
ters within the command string may be in either
upper-case or lower-case letters.
Just before the switcher begins executing a
command string, it sends a leader character to the
host. After the command string has been executed,
the routing switcher returns the string “OK” (with
a single space character before and after the word
“OK”), followed by a trailer character (~) and a
CR character, to the host. This indicates that the
command has executed successfully. If an error
occurs within any command of a command string,
the remainder of the command string is ignored
and the switcher returns the string “ERROR”,
followed by a trailer character and CR character,
to the host. An error consists of an unknown
command name or bad arguments to a command.
Leader and Trailer.
“*” is a command string leader and “!” is a
command string trailer.
The simplest possible command string would be
“*!”, which consists of the leader and trailer
characters but no command between them. This
command string would generate the response
“* OK!” followed by “CR”. This can be useful
for verifying that the serial link to the switcher is
operational.
Following is the command set:
Syntax Example Description
I
I Capabilities inquiry.
S S Status inquiry.
U {0 | 1} U0 Update request on/
off.
X out, in, lvl
X12,9,2 Connect crosspoint.
Z in, in... Z13,12,8 Connect AFV.
“I”: Capabilities Inquiry
The command “I” requests that capability infor-
mation be returned to the host. The information is
sent as a string of characters. The first characters
are a space followed by “I”, the next characters
are the command letters that are implemented as
commands, and the last character is “~” (tilde).
For example, the command:
*I!
might return the following string:
*IILSX~ OK !<CR>
indicating that the switcher supports the “I”, “L”,
“S”, and “X” commands from the host.
“S”: Status Inquiry
The command “S” requests that status information
be returned to the host. The status information is
sent as a string of L x O substrings, where L =
number of levels and O = number of outputs.
Each level/output combination generates a single
substring of status. Thus, a 2-level 16 output
router would generate 2x16 = 32 substrings of
status command output. The length of each