DCP Series Telcon Message Manual - Public Support Login - Unisys

X.25 PSCS Diagnostic Codes
Notes:
1. “Layer 3/4 Platform generated” implies that the values of the codes are greater
in value (255 decimal) than what would be allowed to be sent across an X.25
network.
2. Diagnostic codes that PSCS generated defines, and will send out on the network.
A DTE, attached either directly to the DCP (DAD) or across a network, may
receive these diagnostic codes in clear packets. In some cases, the codes are
passed up by the layer 3 to the layer 4 program.
3. Not all diagnostic codes need apply to a specific network, but those used are as
coded in the table.
4. A given diagnostic need not apply to all packet types (for example, reset
indication, clear indication, restart indication, registration confirmation, and
diagnostic packets).
5. The first diagnostic in each grouping is a generic diagnostic and can be used in
place of the more specific diagnostics within the grouping. The decimal 0
diagnostic code can be used in situations where no additional information is
available.
6. This diagnostic may also apply to a maintenance action within a national
network.
7. Diagnostics 224 through 255 support the OSI Network Service Definition.
8. In certain situations, multiple diagnostic codes may apply. For example, if a
timer has expired and a (RESTART, CLEAR, or RESET) REQUEST packet is to
be retransmitted, then the DTE may use the diagnostic code associated with the
original error or the corresponding “timer expired” diagnostic code.
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