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New Member

T1 Clock Source on AS5400


I am configuring an AS5400 which has an 8T1 card. I want all the the 8 T1's to receive clock from one single source that is the first T1 port on the card. How can I do this. The IOS version I am using is 12.2(11)T8 & I am configuring a T1 CAS circuit.

Thanks in Advance



Re: T1 Clock Source on AS5400

Configure the first T1 to recieve clock from the external clock source like CO. command for that is

controller t1 0/0

clock source line primary

and the other T1 ports to take the clock from the 0/0 T1 line, that is

controller t1 1/0

clock source internal

controller t1 2/0

clock source internal

clock source {line [primary] | internal | free-running}

New Member

Re: T1 Clock Source on AS5400

Below may help taken from CCO. It applies to 5400 as well.


To configure the clock source and priority of the clock source used by the time-division mulitiplexing (TDM) bus on the dial shelf of the Cisco AS5800, use the dial-tdm-clock global configuration command. To return the clock source and priority to the default values, use the no form of the command.

[no] dial-tdm-clock priority number {external {e1 | t1} [120ohm] | freerun | trunk-slot slot port port}

Syntax Description

priority number

Specify the priority of the clock source. The range is 1 to 50. Priority 1 is the highest priority and 50 is the lowest.


Specify the priority of an external clock source. The external clock source is connected to the front panel of the dial shelf controller (DSC) card.

{e1 | t1} [120ohm]

Specify priority of the E1 (2.048 MHz) or T1 (1.54 MHz) external clock source. The default value of the external coaxial cable impedance is 75 ohm. Specify the 120ohm option if a 120 ohm coaxial cable is connected.


Specify the priority of the local oscillator clock source.

trunk-slot slot

Specify the priority of the trunk card to provide the clock source. The slot number is from 0 to 5 (these are the only slots capable of providing clock sources).

port port

Specify the controller number on the trunk used to provide the clock source. The port number is from 0 to 28. The T1 and E1 trunk cards each have 12 ports. The T3 trunk card has 28 ports.

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