Filter
Top Products
Testing
8-12
8700-A2-GB20-00
April 2000
Telco-Initiated Payload Loopback
The Hotwire 8747 and 8777 Termination Units support payload loopback as
specified in AT&T TR 54016 and ANSI T1.403. A Telco-initiated line loopback
loops the received signal on the DSX-1 interface back to the DSX-1 interface.
Framing, CRC, and FDL bits are regenerated at the point of the loopback, and
BPVs are removed. DSL time slots mapped to the DSX-1 port are sent all ones.
CAP
DSL
Port
DSX-1
Port
CAP T1
LIU
FramerFramerTransceiver
99-16253
All Ones
Telco
Telco-Initiated Remote Line Loopback
If Remote Telco Loopback is enabled, a Telco-Initiated Line Loopback loops
received data at the remote unit and passes it back to the Telco through the local
unit.
The following figure shows the data flow for a remote Telco-initiated payload
loopback.
CAP
DSX-1
Port
CAPT1
LIU
Framer Framer Transceiver
99-16626
CAP CAP T1
LIU
FramerFramerTransceiver
Telco
Local Remote
DSX-1
Port
AIS
DSL
Telco-Initiated Remote Line Loopback cannot be used in cross-connect mode.