Use a Cisco router FXS as PBX subscriber

I’m a little bit confuse so before start with cli commands I need a small guide.

I have a Cisco 2600 router with several FXS boards. The router hardware is ok because I’m using other like destination and have others FXS ports.

Now I need to setup it as an extension or as a trunk line ?
Sip-ua only have one registration for the same router so I don’t know how to setup it for each voice-port.

Some example to follow? I treat them like FXO with out DID ?

I need to add some configuration via CLI into the freepbx or I can do using the web admin?

Best Regards!

The FXS is active and I have the voice message that the 200 extension do not exist.

If I create it without password it fails.

What is the next step to register this FXS at the PBX?
As trunk or as phone??

router debug:
Call 1
SIP Call ID : [email protected]
State of the call : STATE_ACTIVE (7)
Substate of the call : SUBSTATE_NONE (0)
Calling Number : 200
Called Number : 200
Bit Flags : 0xC04018 0x100 0x0
CC Call ID : 16
Source IP Address (Sig ):
Destn SIP Req Addr:Port :
Destn SIP Resp Addr:Port:
Destination Name :
Number of Media Streams : 1
Number of Active Streams: 1
RTP Fork Object : 0x0
Media Mode : flow-through
Media Stream 1
State of the stream : STREAM_ACTIVE
Stream Call ID : 16
Stream Type : voice+dtmf (1)
Negotiated Codec : g711ulaw (160 bytes)
Codec Payload Type : 0
Negotiated Dtmf-relay : rtp-nte
Dtmf-relay Payload Type : 101
Media Source IP Addr:Port:
Media Dest IP Addr:Port :
Orig Media Dest IP Addr:Port :

I’m sorry, but I’m still not sure where you are trying to go with this. There are lots of interfaces there, and there are lots of ways to connect them to do a lot of reasonably useful things. Can you throw a use-case together to give us some idea where you are trying to end up?

Hi Dave!
Thanks for your response.

For now and only to understand freepbx I only want to set one FXS as an extension.
To call from one FXS port to an other in the same router.

I’m using a 2600 with a high density voice board and a 4 ports FXS vic board.

Best Regards!!


If you can wait a little bit I have a Cisco config for you. Each FXS port becomes an extension, so essentially I transform the Cisco router into a multiple port ATA.

Hi Michel!
That will be great! I understand cisco but I’m a new one with freepbx.
What confuse me a little is where i can set come text setup that I see like examples, like this:

and bla bla

For now all the config I’m doing via the web interface, but those setup exports where they can be imported? Or is part of some CLI commands?

Best Regards!!

voice-port 2/0
dial-peer voice 1 voip
destination-pattern …
session protocol sipv2
session target sip-server
session transport udp
dtmf-relay rtp-nte
codec g711ulaw
dial-peer voice 6363 pots
description Test analog phone.
destination-pattern 6363
port 2/0
authentication username 6363 password xxxx
timer receive-rtp 1200
registrar ipv4: expires 300
sip-server ipv4:
Note that if it’s on the same router, it may not even use FreePBX, working on that part soon.

On FreePBX: All in the GUI
Create extension.
User extension : 6363
Display name : test
secret : xxxx
No different than any other IP Phone.

1 Like

Very thank you Michel!!!

Fully tested work GREAT!

Hi Frank,

Glad it worked for you. I’d like to see the 2600 config (edited).
Also, I’d like to know your use case for it, if it was only a Cisco to Cisco thing you would not ever need freepbx.


Hi Michel!
Yeah I know and I use too with great results, but I never setup a call manager into this routers.

I’m using this because I need the conference call functionality, and using your setup as start I get it working.
I want to implement this because I want to integrate freepbx with a two way radio equipment.
In fact is working but the only think that I can’t change or I don’t know how do it is use VAD for the conference.

The cisco two way radio solution switch the radio TX/RX when the call have audio.

The problem is that the freepbx conference is always streaming even only the Cisco’s port is the only one conference member, not detect the silence and stops the streaming.This set the radio always in TX mode.

If I fix that I have my freepbx linked to my radio system.

Best Regards!

Hi Michel
I setup my router with great results with 4 FXS ports and phones.

But after several minutes all the extensions or ports from router looks like loose registration from server. If I ping from the router Cli to the server’s IP it fail too.

I have some softphones (Zoiper) running in some android cellphones and them never fails.

can be that the server blacklist the router ???

Best Regards!!