Nortel Networks BCM50 manual Describes the functions of the DTM LEDs, DTM LED functions

Chapter 3 Viewing the BCM50 system LEDs 65

DTM LEDs

The DTM has additional LEDs that are not on most other MBMs. Figure 25 on page 65 shows the location of the DTM LEDs.

Figure 25 DTM LEDs

Power LED

Status LED

In service LED

Loopback test LED

Receive LEDs

Transmit LEDs

Table 14 describes the functions of the DTM LEDs.

Table 14 DTM LED functions

LED	Status	Descriptions
Power	–	Refer to “Media bay module LEDs (expansion units only)” for details.
Status	–	Refer to “Media bay module LEDs (expansion units only)” for details.
In service	Flashing	The T1, ETSI, or PRI trunks are out of service because a loopback test is
		running or the DTM is initializing.
Loopback test	On	A continuity loopback test is running.
Receive alarm	On	A problem with the received digital transmission. This half-duplex link does
		not work.
Receive error	On	A small error as a result of degraded digital transmission. Possible causes are
		an ohmic connection, water ingress, or too long a loop.
Transmit alarm	On	The DTM cannot transmit. The DTM sends an alarm indication signal (AIS) to
		the terminating switch. This half-duplex link does not work.
Transmit error	On	The DTM is sending a remote alarm indication (RAI) carrier failure alarm
		(CFA) to the terminating switch. If the transmit alarm is not on, this error
		indicates a far-end or cable problem.
All LEDS	Flashing	The DTM is initializing.

BCM50 Installation and Maintenance Guide