Troubleshooting guide

Troubleshooting Guide
120
MSDN/DPNSS Links
Table 35: MSDN/DPNSS Link Troubleshooting
Symptom Probable Cause Corrective Action
Embedded MSDN/DPNSS
calls fail and all status LEDs
on the T1/E1 MMC are OFF.
Faulty configuration. Verify embedded MSDN/DPNSS is programmed
properly in the following forms:
• Controller Module Configuration
• Framer Configuration –> T1/E1 Framer
Configuration
• Link Descriptor Assignment
• Digital Link Assignment
After the Digital Links form is completed, the red
T1/E1 MMC status LED should come on. This
takes about 15 seconds.
Embedded MSDN/DPNSS
links are “not seizable” and
the red LED is ON.
Faulty configuration or
wiring.
Ensure that the T1/E1 cable is plugged into the
correct RJ-45 port on the T1/E1 MMC.
Verify that the T1/E1 cable is correctly wired. Note
that 1&2 and 4&5 are the relevant pins for the
cable.
Toggle the “Termination Mode” setting in the Link
Descriptor Assignment (either NT or LT). This
change takes about 15 seconds to take affect.
Embedded MSDN/DPNSS
links are “not seizable” and
the green LED is ON.
Faulty configuration. Ensure that the “Address for Message Control”
field in the Digital Link Descriptors form is set
appropriately (either “A” or “B” depending on the
far end).
If the configuration is correct, wait for about 1
minute until the every circuit has finished
negotiating with the far end.
High number of slips. Incorrect configuration of
Network Synchronization
form.
Ensure that the synchronization source being
selected is to a digital PSTN trunk (like PRI or
T1/D4).
User is unable to make an
MSDN link call.
Programming error in Trunk
Attributes form.
Ensure that the Trunk Attributes form is
programmed correctly at both ends of the link.
Specifically, dial-in trunks must have an entry in
the Absorb column. (Enter '0' if no digits are to be
absorbed.) For example, if the Trunk Attributes
form of the Local system is programmed correctly
but the form in the Remote system is not
programmed correctly, MSDN calls will succeed
only from Remote to Local. Calls made from Local
to Remote will fail.
Page 1 of 2