# path ds3 t1 loopback

#### Syntax

path pathChannel ds3 ds3Channel t1 t1Channel loopback
{ local | network { line | payload } }

no path pathChannel ds3 ds3Channel t1 t1Channel loopback

path pathChannel ds3 ds3Channel t1 t1Channel loopback remote
{ line fdl { ansi | bellcore } | payload [ fdl ] [ ansi ] }

no path pathChannel ds3 ds3Channel t1 t1Channel loopback remote

#### Release Information

Command introduced before JunosE Release 7.1.0.

#### Description

Configures a loopback for a T1 channel on a DS3 signal. This command applies to a T1 channel on a DS3 over channelized SONET interface. The no version turns off the loopback.

#### Options

- pathChannel—Number, in the range 1–2147483648, that identifies the path
- ds3Channel—Number, in the range 1–3, that identifies the DS3 channel
- t1Channel—One or more individual T1 channels, ranges of T1 channels, or combination of individual channels and ranges, in the range 1–28 (no spaces); for example, 3,7-15,19-13,27
- local—Loops the router output data back toward the router at the T1 framer; on supported line modules also sends an alarm indication signal (AIS) out toward the network.
- network { line | payload }—Specify the line keyword to loop the data back toward the network before the T1 framer and automatically set a local loopback at the HDLC controllers. Specify the payload keyword to loop the payload data back toward the network at the T1 framer and automatically set a local loopback at the HDLC controllers.
- remote line fdl ansi—Sends a repeating 16-bit ESF data link code word (00001110 11111111) to the remote end requesting that it enter into a network line loopback. Specify the ansi keyword to enable the remote line FDL ANSI bit loopback on the T1 channel, according to the ANSI T1.403 specification.
- remote line fdl bellcore—Sends a repeating 16-bit ESF data link code word (00010010 11111111) to the remote end requesting that it enter into a network line loopback. Specify the bellcore keyword to enable the remote line FDL Bellcore bit loopback on the T1 channel, according to the Bellcore TR-TSY-000312 specification.
- 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. Enables the remote payload FDL ANSI bit loopback on the T1 channel. You can optionally specify fdl and ansi, but it is not necessary.

#### Mode

Controller Configuration