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New Member

Network-clock-select

I am having an issue with fax machines connecting and transmitting.

I have a 2821 router with 4 total PRI connections.

2 connections go to a Mitel PBX and 2 go to the PSTN.

I have a fax machine on the Mitel side try to fax and it fails. If I do a show controllers t1, I see a ton of frame errors on the PRI's to the PBX but not on the PSTN PRI's.

If I switch the clock select from the backplane to on of the PBX PRI's, the PSTN PRI's start throwing errors.

How can I configure these clock sources?

3 REPLIES
Hall of Fame Super Gold

Re: Network-clock-select

You should have pstn line clocking and select, pbx clock internal, participate but no select.

New Member

Re: Network-clock-select

Can you explain this further?

0/0/0 and 0/0/1 are to the PSTN

0/1/0 and 0/1/1 are to the PBX.

Hall of Fame Super Gold

Re: Network-clock-select

pstn lines use line clock and select, pbx internal clock and participate only.

What is that you don't understand ?

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