IBM 3745 Series, Hardware Maintenance Reference

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Problem Determination Aid
Token-Ring Wrap Tests
Using NCP
Under NCP a wrap test is performed at each TIC open command processing as a first step
before inserting itself into the ring.
:
The TIC internal lobe media test, tests the ring up to and including le
logic (relay contact normally closed) pertaining to the position of the IBM 8228 MSAU or equivalent where
the lobe connector is plugged-in (the 8228 is a wiring concentrator).
It also tests the ring up to the point were it is unplugged before the 8228. (that is, at the tailgate, at the
wall connector, and so on.)
The lobe media test is only invoked on the open command and is not performed as a result of the reset or
initialization commands.
Note that a disconnected cable during the lobe media test will cause a lobe wire fault check to appear in
both the display token-ring status function and the ring status field (field E) of the token-ring interconnect
function. (Refer to the
Problem Determination Guide, GA33-0096.)
When a lobe wire fault is detected the TIC will be frozen and the status will remain unchanged until the
next open is issued.
Using TRA Diagnostics
Using the TRA diagnostic routine TG01, a wrap test is also performed up to
and including the 8228 or up to the point at which the ring is unplugged before the 8228.
Diagnostic Section TA0A: The TRM must be 'disconnected' before running the diagnostic section TA0A.
The 'disconnect' command must be performed after each power-OFF to power-ON.
However, no open commands are issued by the diagnostic routine so a lobe wire fault will not be
detected.
Chapter 6. The Token-Ring Subsystem
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