Specifications

Configure Serial Interfaces for CSU/DSU Service Modules
IC-104
Cisco IOS Interface Configuration Guide
Fractional T1/FT/WIC CSU/DSU Service Module Configuration Task List
To configure fractional T1 and T1 (FT1/T1) service modules, perform the tasks described in these
sections:
• Specify the Clock Source
• Enable Data Inversion before Transmission
• Specify the Frame Type of a FT/T1 Line
• Specify the CSU Line Build Out
• Specify FT1/T1 Line-Code Type
• Enable Remote Alarms
• Enable Loopcodes that Initiate Remote Loopbacks
• Specify Timeslots
• Enable T1 CSU WIC
Specify the Clock Source
To specify the clock source for the FT1/T1 CSU/DSU module, use the following command in
interface configuration mode:
Enable Data Inversion before Transmission
Data inversion is used to guarantee the ones density requirement on an alternate mark inversion
(AMI) line when using bit-oriented protocols such as High-Level Data Link Control (HDLC),
Point-to-Point Protocol (PPP), X.25, and Frame Relay.
To guarantee the ones density requirement on an AMI line using the FT1/T1 CSU/DSU module, use
the following command in interface configuration mode:
If the timeslot speed is set to 56 kbps, this command is rejected because line density is guaranteed
when transmitting at 56 kbps. Use this command with the 64-kbps line speed. If you transmit
inverted bit codes, both CSU/DSUs must have this command configured for successful
communication.
To enable normal data transmission on a FT1/T1 network, use the following command in interface
configuration mode:
Command Purpose
service-module t1 clock source {internal | line} Specify the clock source, for the CSU/DSU internal
clock or the line clock.
Command Purpose
service-module t1 data-coding inverted Invert bit codes by changing all 1 bits to 0 bits and all 0
bits to 1 bits.
Command Purpose
service-module tx1 data-coding normal
or
no service-module t1 data-coding inverted
Enable normal data transmission on a T1 network.