Comtech EF Data RCS20 - Manual (Page 150)

RCS20 M:N Redundancy Switch Revision 15
Remote Operations MN-RCS20 and CD-RCS20
A–8
DIRECTLY-ADDRESSED EQUIPMENT MULTI-DROP OVERRIDE ID
DMD15 Demodulator 21
DMD15 Modem 22
DVB3000/DVB3030/DM45 Video Modulator 23
RCS20 M: N Switch 24
RCS10 M: N Switch 25
RCS11 1:1 Switch 26
DMD2401/VHS-101/VME2401 Modem 27
Reserved for future equipment types 28-31
IMPORTANT
Multi-drop override IDs 01 or 02 can be used interchangeably to broadcast a message to a
DMD-3000/4000 Modem, DMD-4500/5000, or a DMD20 Modem. Comtech EF Data
recommends that the multi-drop override IDs be issued only during system configuration as a
bus test tool by experienced programmers, and that they not be included in run-time software. It
is also advantageous to consider the use of multiple bus systems where warranted by a
moderate to large equipment complement. Therefore, if an RCS20 switch is queried for its
equipment type identifier, it will return a "24."
A.1.6 Software Compatibility
The COMMSPEC, operating in conjunction within the RLLP shell, provides for full forward and backward
software compatibility independent of the software version in use. New features are appended to the end
of the DATA field without OPCODE changes. Older software simply discards the data as extraneous
information without functional impairment for backward compatibility.
If new device-resident or M&C software receives a message related to an old software version, new
information and processes are not damaged or affected by the omission of data.
The implementation of forward and backward software compatibility often, but not always, requires the
addition of new Opcodes. Each new function requires a new Opcode assignment if forward and backward
compatibility cannot be attained by other means.
When Radyne equipment is queried for bulk information (Query Mod, Query Demod, etc.) it responds by
sending back two blocks of data; a non-volatile section (parameters that can be modified by the user) and
a volatile section (status information). It also returns a count value that indicates how large the Non-