Grass Valley Performer SD - Manual (Page 150)

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Section 3 — Operation & Service
Performer ASCII Protocol
Performer ASCII allows control of the Performer from a host
terminal or computer using standard ASCII characters. Multiple
Performers, each assigned a unique address, may be controlled
over a common RS422 bus. All characters are 7-bit ASCII (the
eighth data bit out of the Performer port is ignored). A ninth data
bit may be used for parity if desired.
Command Line
A command line consists of series of bytes in the following format:
All bytes are hex ASCII (characters 0-9 [30H-39H] and A-F [41H-
46H]) ), except for . A hex ASCII character specifies 4 bits or
1 nibble of information and is used in high/low pairs to specify a
complete byte of information. Received ASCII nulls (00H), spaces
(20H), and line feeds (0AH) are ignored and are not included in
the byte count.
Command bytes have the following values:
REQUIRED carriage return character (0DH)
0-F, high nibble of Performer switch 1 address
0-F, low nibble of Performer switch 1 address
0-F, high nibble of byte count for
0-F, low nibble of byte count. Count must not
exceed 251 (FBH).
0-9, A-Z. Zero or more command strings (see
Command Strings). Number of characters
is
If the value is different from the value set at
Performer switch S1, the command and all subsequent characters
are ignored by the Performer until a new message is initiated
using a carriage return. The carriage return purges previously
received data, and must start each command line.