ADC ETU-751C - Manual (Page 16)

Overview 700-701-100-02
6 August 9, 2002 UTU-701 and ETU-751 List 1
Table 4 defines the system states indicated by the front panel LEDs. When power is applied to the unit, one of the
LEDs listed in Table 4 will always be on.
Table 4. Line and Desktop Unit Front Panel LED Indications
LED Mode Description
HDSL SYNC LED Steady green
Slow blinking
Off
HDSL loop is ready to transmit and receive data across all spans.
HDSL loop acquisition is in progress for local span.
HDSL loop is not configured.
HDSL ALM LED Steady red
Pulsing red
Off
Loss of sync word (LOSW); or the margin is below the set margin
alarm threshold; or Errored Seconds (ES) count is above
threshold on any span.
Pulses for every ES on any span.
Normal transmit or receive data is in progress.
I/F ALM LED Steady red Loss of Signal (LOS) alarm due to loss of G.703 signal or Loss of
Clock (LOC) alarm due t
o loss of external clock (when using EXT
timing).
LPBK LEDs (a) LOC REM
Steady yellow Off Local HDSL analog loopback is active.
Off Off No loopbacks are active.
Blinking yellow Off Local interface loopback is active.
Off Steady yellow Remote loopback is active.
Blinking yellow Blinking yellow A loopback away from the local equipment is active.
(a) The LOC and REM LPBK LEDs are read in unison.