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New Member

FXS and PBX question

I have an FXS port on a router and I have to connect it to our PBX, so users inside will choose an extension and get routed through the router, instead of PSTN (I have regular telephony behind the PBX and plan to use VoIP over Internet, between 2 remote offices - on-net toll bypass). How can I do this, or where can I find information for configuring FXS for PBX connectivity and how can I configure the PBX?

Thanks!

5 REPLIES
New Member

Re: FXS and PBX question

You stated you have an fxs port on the router and is attached to a PBX.

First you should make sure the PBX port is an FXO.

there should be no voltage supplied between tip and ring. ou can test this by using a volt meter, or plugging a phone into that port and listening for dial-tone. If you hear dial-tone, it is also and fxs, and you have purchased the wrong interface for the router.

Please refer to the EIA-464b standard for the correct definitions of FXS/FXO if you have any doubt.

If the port on the PBX is an FXO, you can configure the router to do either a trunk, plar, or route based on digits input.

Since you have FXS in the router, I would suggest collecting digits after an initial trunk selection digit is dialed.

ex. user picks up phone at side A and dials 8 for site B access to the router.

The local router at site A provides dial-tone to the user. The user then enters the number of the extension at the other site. (i.e. 8, 1234)

the remote router will then get the call and can be programmed to play out 1234 to the PBX. The PBX will then route the call as it would any other local extension.

below are a few URLs that shold get you started...

Jeff

http://www.cisco.com/warp/public/788/voip/dial_peer_concepts.htm#first

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fvvfax_c/vvfpeers.htm

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fvvfax_c/vvfvoip.htm

New Member

Re: FXS and PBX question

OK, so, to my understanding, the PBX thinks it's a CO analog line (pots) and configure it to route over it for a special extension. How then can I configure the router FXS ports to communicate with the PBX for a "route based on digits input"? I didn't find anything on CCO for FXS, only for E&M.

Thank you!

New Member

Re: FXS and PBX question

Hi,

Here is a partial config that should get you started...

!

voice-port 1/0/0

!

voice-port 1/0/1

!

dial-peer voice 1 pots

destination-pattern +321

port 1/0/0

!

dial-peer voice 2 pots

destination-pattern +322

port 1/0/1

!

dial-peer voice 102 voip

destination-pattern ...

session target ipv4:10.102.1.1

!

dial-peer voice 103 voip

destination-pattern +33.

session target ipv4:10.103.1.2

!

dial-peer voice 104 voip

destination-pattern +35.

session target ipv4:10.104.1.2

--More--

New Member

Re: FXS and PBX question

Thanks for your input. Do I need to have a "connection trunk" on voice-port or bother with "no signal loop-start", since I have a FXS and not an E&M? Or just connect my FXS to a FXO on PBX (not like Router-E&M to PBX-E&M) do a trunk selection on PBX based on a special extension and do nothing else on the voice-port on the router (thinks is connected to a phone and provides battery and dial tone, like normal).

Thanks again!

New Member

Re: FXS and PBX question

No connection-trunk is needed, this partial config comes off a working router. Just FXO to FXS and either a speical extension(s) or an access code (i.e. 85 and then the extension) needs to be programmed in the PBX.

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