CANOGA PERKINS 2461 E1 Modem - Manual (Page 47)

EdgeAccess Universal Chassis System
2461 Modem User Manual 5-5
5.4.1 Normal Operation
In normal transparent operation, the data from the user equipment enters the modem at its
transmit interface, passes through the proprietary fiber optic network (See Figure 34), outputs at
the receive interface on the remote end, and vice versa.
Figure 34. The modem in Normal Operation
5.4.2 Local Loopback Operation
When activated, the Local Loopback test will cause all data transmission from the local user
device to be looped back toward the receive side of that same device. The local modem under
local loopback will transmit AIS to the remote user device (Figure 35). The data from the remote
user device will not be looped back.
Figure 35. The modem in Local Loopback Operation
Optical
Link
Normal Operation
LIU
Tx
Rx
Logic
Tx
Rx
LIU
Mux-
Enc
Demux-
Dec
Demux-
Dec
Mux-
Enc
Fiber Logic Fiber
Local Loopback Operation
Optical
Link
LIU
Tx
Rx
Logic
Tx
Rx
LIU
AIS Mux-
Enc
Demux-
Dec
Demux-
Dec
Mux-
Enc
Fiber Logic Fiber