Specifications

Enable Remote FDL Loopbacks
Configuring Serial Interfaces IC-91
• Total bit errors
• Total bits received
When the T1 channel has a BERT test running, the line state is DOWN. Also, when the BERT test
is running and the Status field is Not Sync, the information in the total bit errors field is not valid.
When the BERT test is done, the Status field is not relevant.
The t1 bert pattern command is not written to NVRAM because it is only used for testing the T1
channel for a short predefined interval and to avoid accidentally saving the command, which could
cause the interface not to come up the next time the router reboots.
Enable Remote FDL Loopbacks
You can perform the following types of remote Facility Data Link (FDL) loopbacks on a T1 channel:
• Remote payload FDL ANSI—Sends a repeating, 16-bit ESF data link code word (00010100
11111111) to the remote end requesting that it enter into a network payload loopback.
• Remote line FDL ANSI—Sends a repeating, 16-bit ESF data link code word (00001110
11111111) to the remote CSU end requesting that it enter into a network line loopback.
• Remote line FDL Bellcore—Sends a repeating, 16-bit ESF data link code word (00010010
11111111) to the remote SmartJack end requesting that it enter into a network line loopback.
To enable loopbacks on a T1 channel, use the following commands beginning in global configuration
mode:
Note The port adapter and port numbers for the CT3IP are 0.
Configure PA-E3 and PA-2E3 Serial Port Adapters
The PA-E3 and PA-2E3 serial port adapters are available on Cisco 7200 series routers, on Cisco 7500
series routers, and on Cisco 7000 series routers with the 7000 Series Route Switch Processor
(RSP7000) and 7000 Series Chassis Interface (RSP7000CI). These port adapters provide one
(PA-E3) or two (PA-2E3) high-speed, full-duplex, synchronous serial E3 interfaces and integrated
data service unit (DSU) functionality.
Step Command Purpose
1 interface serial
sl
ot/port-adapter/port:t1-channel
(Cisco 7500 series and Cisco 7000
series routers with the RSP7000 and
RSP7000CI)
or
interface serial slot/port:t1-channel
(Cisco 7200 series)
Select the T1 channel (values are 1 to 28) on the CT3IP
and enter interface configuration mode.
2 loopback remote payload [fdl] [ansi] Enable the remote payload FDL ANSI bit loopback on
the T1 channel.
3 loopback remote line fdl {ansi |
bellcore}
Enable the remote line FDL ANSI bit loopback or
remote SmartJack loopback on the T1 channel.