ADTRAN Total Access 1240 - Manual (Page 127)

Section 5, User Interface - Menu Descriptions
61179605L5-5B 5-87
Remote Dual-Sided Loopback
The remote dual-sided loopback provides a bidirectional loopback at the Network Termination
Unit (NTU), as shown in
Figure 5-68 .
Figure 5-68. Remote Dual-Sided Loopback
Remote Customer Loopback
The remote customer loopback provides a loopback at the NTU in the customer direction, as
shown in
Figure 5-69 . An Alarm Indication Signal (AIS) is injected into the network side.
Figure 5-69. Remote Customer Loopback
Remote Network Loopback
The remote network loopback is initiated at the NTU in the network direction, as shown in
Figure 5-70 . AIS signal is injected into the customer side.
Figure 5-70. Remote Network Loopback
The initiation or removal of any loopback test does not interfere with any interface not being
tested. Loopbacks can be set by one source and removed by another source. If the SHDSL line
is dropped, or if the NTU is power cycled, all active loopback tests are released.
NTU LTU
LTU
TX AIS
NTU
LTU
TX
AIS
NTU