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Configuring the T1 Physical Link
are ignored when a port is configured for SF framing. See "Framing" for information on
configuring framing.
The two standards supported for FDL are ATT, described by the ATT 54016
specification, and ANSI, described by the T1.403 standard. The default value is off. To
configure FDL, use the following command:
config ports <portlist> t1 fdl [off | att | ansi]
Framing
Framing is used to synchronize data transmission on the T1 line. Framing allows the
hardware to determine when each packet starts and ends. The two choices for framing
are Super Frame (SF), also known as D4, and Extended Super Frame (ESF). The ESF
scheme is a newer standard and is enabled by default. To choose the framing scheme,
use the following command:
config ports <portlist> t1 framing [esf | sf]
If you choose to use SF framing, you should disable yellow alarm detection for the T1
line. SF framing may generate false yellow alarms. See "Yellow Alarms" on page 2-5 for
more details.
Inband Loopback Detection
When inband loopback detection is enabled, a specific sequence of data in the signal
payload from the remote end of the T1 link will cause the local end to enter network
line loopback mode and send any received signal back to the remote end. Inband
loopback detection is only possible if the FDL standard is configured as ATT. See
"Facility Data Link" on page 2-3 for more details. By default, inband loopback detection
is off. See "Loopback" on page 2-6 for more information about loopback modes. To
configure inband loopback detection, use the following command:
config ports <portlist> t1 lbdetect [off | inband]
Linecoding
Linecoding is the convention used to encode signals for transmission over the T1 line.
You can choose from two linecoding standards, bipolar eight zero suppression (B8ZS) or
alternate mark inversion (AMI). The default value is B8ZS. To configure linecoding, use
the following command:
config ports <portlist> t1 linecoding [b8zs | ami]
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WM-4T1i Module Installation and User Guide
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