ADC HDSL4 Benutzerhandbuch

Once the H4TU-C is installed, verify that it is operating properly. To do this, monitor the following:

Status LED

Status messages reported by the front-panel display (see 

If there is no downstream device installed:

Verify that the H4TU-C powers up. The front-panel display illuminates and reports status messages. (See 

 for a list of messages.)

Verify that the H4TU-C attempts to communicate with downstream devices (status LED flashes red). Even 
if a downstream device is not present, the following events should occur:

The front-panel display reports various four-character status messages.

The H4TU-C again attempts communication until a downstream device is detected.

If a downstream device has been installed:

Verify that the H4TU-C powers up. (The front-panel display illuminates and reports various status messages.)

Verify that the H4TU-C attempts to communicate with downstream devices (status LED flashes red). One of 
the following occurs:

If downstream devices are successfully identified and the HDSL4 loop synchronizes, the H4TU-C status 
LED lights steady green. The H4TU-C reports normal margin and loop attenuation messages on the 
front-panel display.

If downstream devices are not successfully identified, the H4TU-C reports four-character status 
messages. The H4TU-C attempts communication again and reports four-character status messages. The 
H4TU-C repeats this cycle until a downstream device is detected.

If there is more than one span, verify that each subsequent span synchronizes normally by monitoring the 
front-panel display messages. 

If a remote unit is installed, verify that the last span synchronizes normally. The H4TU-C status LED should 
light a steady green and the front-panel display should report normal margin messages. 

Verify that a valid DS1 signal has been applied to the H4TU-C and the H4TU-R.

If no DS1 signal is being applied to either the H4TU-C or the H4TU-R inputs, then the appropriate DS1 
alarms (LLOS or RLOS) display on the front panel and the status LED flashes red.

If a valid DS1 signal is being supplied to the H4TU-C and H4TU-R, then DS1 alarm indications should 
be absent and the status LED should be steady green.