Troubleshooting - JDS Uniphase HST-3000 Product Manual

3
Figure 2. D-Channel Decode Results
Figure 3. Summary Results
HST-3000 ISDN BRI SIM

Troubleshooting

Non-intrusive bi-directional monitoring of in-service D-channel signaling
messages make troubleshooting a new ISDN turn-up easier. For ISDN BRI
circuits, the technician can access the D-channel on the U interface. If the problem
can not be easily isolated at the customer premises or at the switch, then section-
alization can be accomplished by using the U-Monitor mode to monitor between
the NT1 and LT devices. Used in tandem, the technician can sequentially replace
each piece of premise equipment to identify the source of errors. Results can be
displayed on-screen or stored for later retrieval and output via RS-232, USB or
Ethernet connectivity—standard with each base unit.
D-Channel Decodes Analysis
D-channel decodes help to analyze such factors as call establishment status,
uncompleted call and error message causes, and equipment "lock up" issues. The
HST-3000 can monitor layer 2 (LAPD) and layer 3 (Q.931) cause code messages
on the D-channel in both terminate and monitor modes. Layer 2 results give
technicians the ability to check link and D-channel status, verify LAPD frames,
and check utilization rates. Following link establishment, Layer 3 decodes allow
technicians to verify such factors as call state, who made or dropped the call, why
the call was dropped, where the call is being carried (TEI), and call types.