ADTRAN T1 CSU ACE - Manual (Page 25)

Chapter 1. General
61203022L1-1B T1 CSU ACE User Manual 25
LOOPBACK
The T1 CSU ACE supports four types of loopbacks. With the first two,
the unit loops the signal received from the network back to the network
and transmits an unframed
all 1s pattern to the CPE. The signal
received from the CPE is ignored.
The first type of loopback, Manual Network Loopback (see Table 1), is
initiated by switching on the
NET LB switch on the back of the unit. The
NET MAN LB LED will turn On and the loopback will continue until it
is switched off. See Figure 5 on page 26.
The second type of loopback, Network LB , is activated by sending the
unit a 1-in-5 pattern (10000) from the network side for five seconds. The
NET RMT LB LED will turn On until it is cleared by sending a 1-in-3
pattern (100) for five seconds. The patterns may be Unframed or
Framed (SF or ESF).
The third type of loopback, Manual Equipment Loopback
(see Table 1), is initiated by the
Equip LB switch on the back of the unit.
It will continue until Equip LB is switched off. With the Equip LB , the
unit loops the signal received from the CPE equipment back to the CPE
equipment, and transmits an unframed
all 1s pattern to the network.
The signal received from the network is ignored. The EQ MAN LB LED
will illuminate when the loopback is in progress. See Figure 5 on page
26.
The fourth type of loopback, Equipment Remote Loopback, is activated
by sending the unit a 1-in-5 pattern (10000) from the CPE side for five
seconds. The
EQ RMT LB will illuminate until it is cleared by sending a
1-in-3 pattern (100) for five seconds. The patterns may be Unframed or
Framed (SF or ESF).
Table 1. Manual Loopbacks Switch Position Settings
LOOPBACK Type POSITION 6 POSITION 7
Network Up Down
Equipment Down Up