
Chapter 10 Testing, Troubleshooting, and Diagnostics 425
Business Communications Manager - Management User Guide
Refer to Business Communications Manager Installation and Maintenance Guide for information
on replacing components.
Refer to the following sections for more information:
• “Digital trunk module problems” on page 425
• “Monitoring the T1 or PRI signal” on page 426
Digital trunk module problems
1 Choose Resources, Media Bay Modules and the bus that the module is on to verify that
the DTM is enabled and that the lines are provisioned. For more information, refer to the
procedure, “Media Bay Module status” on page 427.
Check the LEDs on the front of the DTM.
• Receive Alarm: yellow LED on indicates a problem with the digital transmission being
received. This half-duplex link is unusable.
• Receive Error: yellow LED on indicates a minor error as a result of degraded digital
transmission. Possible causes are an ohmic connection, water ingress, or too long a loop.
• Transmit Alarm: red LED on indicates an inability to transmit. Alarm indication signal (AIS)
is being transmitted to the terminating switch. This half-duplex link in unusable.
Note: Before you replace the Business Communications Manager system, disconnect all
central office and station lines from the Business Communications Manager system.
Power down the system by unplugging it.
Front view
Telecom
Loopback
connector
Transmit LEDs
Receive LEDs
Continuity loopback
Loopback Test LED
In Service LED
Power LED
Status LED
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