Hardware manual

loopback (T3 controller)
Interface Commands IR-141
loopback (T3 controller)
To loop the entire T3 (all 28 T1 channels) on the Channelized T3 Interface Processor (CT3IP) in
Cisco 7500 series routers, use the loopback controller configuration command. Use the no form of
this command to remove the loopback.
loopback [local | network | remote]
no loopback
Syntax Description
Default
Disabled
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.3.
Use this command for troubleshooting purposes.
You can also loopback each T1 channel by using the loopback interface configuration command.
For more information, refer to the “Troubleshoot the T3 and T1 Channels” section in the
“Configuring Serial Interfaces” chapter of the Cisco IOS Interface Configuration Guide.
Example
The following example configures the CT3IP for a local loopback:
controller t3 3/0/0
loopback local
Related Commands
You can use the master indexes or search online to find documentation of related commands.
loopback remote (interface)
local (Optional) Loops the data back toward the router and sends an
AIS signal out toward the network.
network (Optional) Loops the data toward the network at the T1 framer.
remote (Optional) Sends a far-end alarm control (FEAC) request to the
remote end requesting that it enter into a network line loopback.
FEAC requests (and therefore remote loopbacks) are only
possible when the T3 is configured for C-bit framing. The type
of framing used is determined by the equipment you are
connecting to (for more information, see the framing controller
command).