Comtech EF Data OMS11 - Manual (Page 68)

OMS11 1:1 Redundancy Switch Appendix B
TM133 – Rev. 1.1 B- 5
B.0.4 Global Response Operational Codes
In acknowledgment (response) packets, the operational code field of the message
packet is set to 0 by the receiving devices when the message intended for the device is evaluated
as valid. The device that receives the valid message then exchanges the with the
, sets the to zero in order to indicate that a good message was
received, and returns the packet to the originator.
This "GOOD MESSAGE" opcode is one of nine global responses. Global response opcodes are
common responses, issued to the M&C computer or to another device that can originate from and
are interpreted by all Radyne equipment in the same manner. These are summarized as follows
(all opcode values are expressed in decimal form):
RESPONSE OPCODE DESCRIPTION OPCODE
Good Message 000
Bad Parameter 255
Bad Opcode 254
Bad Checksum 253
Command Not Allowed in LOCAL Mode 252
Command Not Allowed in AUTO Mode 251
Bad Destination 250
Unable to Process Command 249
Packet Too Long 248
Table 2. Response OPCODES
B.0.5 Software Compatibility
The DMD15 RLLP is not software-compatible with the following previous Radyne
products: RCU5000 and DMD4500. These products may not occupy the same bus
while using this protocol as equipment malfunction and loss of data may occur.
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.