Specifications

Sub Rate Data Ports 8-7
SRU Ports SRU port User Screens and Settings
LB
The Loopback setting allows you to activate local loopbacks on the SRU port. These settings
are off, toward the dte (DTE), and toward the net (network). Figure 8-3 shows a diagram of
the local loopback conditions.
Figure 8-3. Local Loopbacks
LB GEN
The Loopback Generate setting generates inband diagnostic codes that are sent to the remote
equipment These codes are compatible with DDS networks, and allow you to command a
latching loopback at remote DDS equipment. You can start loopbacks at the remote ocu
(Office Channel Unit), dsu (Data Service Unit), or csu (Channel Service Unit). Figure 8-4
through Figure 8-5 show the loopbacks locations. You can also turn each loopback off.
Note that loop-up and loop-down commands cannot be implemented for two ports of the same
port simultaneously. You must finish all loopback operations on one port before attempting
them on another port.