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New Member

FXS port seizing

I have a 2 Port FXS module in a 2621 router. When I connect any Northern Telecom Unity phone into port 1/0/0 and go off-hook, both FXS ports go off-hook and I cannot use the second voice-port. When I move the phone to port 1/0/1, the phone only siezes that port and I can use port 1/0/0. There are no hardware problems because I don't have the problem with any other phone I plug into port 1/0/0.

Is there a way to configure the 2600 to ensure that it will not seize the second port when a phone connected to 1/0/0 goes off-hook?

Thanks

4 REPLIES
Silver

Re: FXS port seizing

Theres no way to CONFIGURE the router to sieze both the ports, but i would not eliminate hardware just yet. Something with the battery when you connect the Northern telecom phone is out of whack. So let me ask you, have you tried putting your FXS card in the other slot on the NM-2V, i would be interested in knowing what happens. I have seen this issue before and it has always been hardware for the enitre NM-2V.

You could try putting some sort of Voltmeter to see what voltage comes back, although im not sure that would cause the problem it would be interesting to note a discrepency.

New Member

Re: FXS port seizing

I tried differrent FXS modules, NM-2V's, routers, Unity phones, changed slots and even code and I can still reproduce the problem. As for the volt meter, I do not have those resources.

Thank-you!

Gold

Re: FXS port seizing

See this URL for info:

http://www.cisco.com/en/US/partner/tech/tk652/tk653/technologies_tech_note09186a0080094fac.shtml#info

The summary is that some more sophisticated 2-line phones will use the outer pair (2 & 5) as well as the normal inner pair (3 & 4). It seems that the VIC-2FXS lets you "borrow" port 1 and its DSP resources for the optional second line on port 0.

I don't know of a way to convince the router to ignore the second pair. However, clipping the second pair would pretty decisively take care of the issue. Make a new telephone cord with only the inner pair (3 & 4) wired up.

New Member

Re: FXS port seizing

That was the answer!

Thank-you!

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