Comtech EF Data HPCST-5000 - Manual (Page 152)

Programming Guide for Redundant Controller High-Power TWTA Satellite Terminals
A–4 Rev. 1
Table A-1. Header Byte Codes
Message Mode Header Byte Code Ending Byte Code
Non-Printable ASCII STX (HEX 02H) ASCII ETX (HEX 03H)
Printable ASCII “{” (HEX 7BH) ASCII “}” (HEX 7DH)
A.2.1.2 Primary Address Byte
The primary address byte is the poll address of the redundant system controller. The
primary address byte can be any letter from ASCII A to ASCII Z (capitals only).
SW1 on the rear of the controller determines the poll address (primary address) of the
redundant system controller.
A.2.1.3 Secondary Address Byte
If the secondary address is ASCII Z, the controller accepts the message as a controller
message. If the secondary address is ASCII Y, the controller passes the message to all
TWTAs. If the secondary address byte is not Z or Y, the controller directs the message to
the TWTA with the same poll address as the secondary address. Switches on the rear
panel of the TWTAs determine the secondary address of the TWTAs.
The poll addresses assigned to the redundant system controller and all TWTAs included
in the system must be known by the user. The TWTA poll addresses are set with SW1 on
the rear panel of the TWTAs.
A.2.1.4 Command Byte
If the secondary address is Z, the redundant controller will act upon the command
represented by the command byte. The redundant controller command set is discussed in
Section A.3.
For a secondary address of Y (or a valid TWTA address), the TWTA(s) will act upon the
command represented by the command byte. The TWTA command set is summarized in
Section A.4.
A.2.1.5 Parameters
When command parameters are required, they are placed in this message element.
Redundant controller parameters are discussed in Section A.3. TWTA command
parameters are summarized in Section A.4.