Hardware manual

loopback remote (interface)
IR-146
Cisco IOS Interface Command Reference
loopback remote (interface)
To loop packets through a CSU/DSU, over a DS-3 link or a channelized T1 link, to the remote
CSU/DSU and back, use the loopback remote interface configuration command. To remove the
loopback, use the no form of this command.
loopback remote {full | payload | smart-jack}[0in1 | 1in1 | 1in2 | 1in5 | 1in8 | 3in24 | qrw |
user-pattern 24bit-binary value]
no loopback remote {full | payload | smart-jack}
loopback remote [2047 | 511 | stress-pattern pattern number]
no loopback remote
Note The keywords full, payload, smart-jack, 0in1 through 3in24, qrw, and user-pattern
24bit-binary value apply to the fractional T1/T1 CSU/DSU module. The keywords 2047, 511, and
stress-pattern apply to the 2- and 4-wire 56/64-kbps CSU/DSU module. The features for each
module are grouped and described in the following two syntax descriptions.
Syntax Description for FT1/T1 CSU/DSU Modules
full Transmit a full-bandwidth line loopback request to a remote device, which is
used for testing.
payload Transmits a payload line loopback request to a remote device, which is used for
testing the line and remote DSU.
smart-jack Transmits a loopback request to the remote smart-jack, which some service
providers attach on the line before the customer premises equipment (CPE).
You cannot put the local smart-jack into loopback.
0in1 (Optional) Transmits an all-zeros test pattern used for verifying B8ZS line
encoding. The remote end my report a loss of signal when using alternate mark
inversion (AMI) line coding.
1in1 (Optional) Transmits an all-ones test pattern used for signal power
measurements.
1in2 (Optional) Transmits an alternating ones and zeroes test pattern used for testing
bridge taps.
1in5 (Optional) Transmits the industry standard test-pattern loopback request.
1in8 (Optional) Transmits a test pattern used for stressing timing recovery of
repeaters.
3in24 (Optional) Transmits a test pattern used for testing the ones density tolerance
on AMI lines.
qrw (Optional) Transmits a quasi-random word test pattern, which is a random
signal that simulates user data.
user-pattern
24bit-binary
value
(Optional) Transmits a test pattern that you define. Enter a binary string up to
24 bits long. For the fixed patterns such 0in1 and 1in1, the T1 framing bits are
jammed on top of the test pattern; for the user-pattern, the pattern is simply
repeated in the timeslots.