CANOGA PERKINS 2461 E1 Modem - Manual (Page 50)

EdgeAccess Universal Chassis System
5.4.3 Remote Loopback
When activated, the Remote Loopback test will cause all data transmission from the local user
device to be looped back after the data Decoder/Encoder functional block in the remote modem.
The remote modem under local loopback will transmit AIS to T1/E1 Line Interface (See
Figure 36).
Figure 36. The modem in Remote Loopback Operation
5.4.4 Remote Loopback with BERT
When activated, the Remote Loopback with BERT test will cause all data transmission from the
local user device to be looped back after the data Decoder/Encoder functional block in the remote
modem. An internal BERT is activated in the local unit which transmits a random pattern data at
payload rate to the remote end and detects the errors received (Figure 37). The remote modem
under local loopback will transmit AIS to T1/E1 Line Interface.
Figure 37. Remote Loopback with BERT
Optical
Link
Logic LIU
Rx
Tx
Rx
LIU
Mux-
Enc
Demux-
Dec
Demux-
Dec
Mux-
Enc
Fiber Fiber Logic
Tx
AI S
Optical
Link
Logic LIU
Rx
CHK
QRSS
AIS
LIU
Mux-
Enc
Demux-
Dec
Demux-
Dec
Mux-
Enc
Fiber Fiber Logic
GEN
QRSS
Tx
AI S
2461 Modem User Manual 5-6