SIP gateway <-> IP phone?


Since I'm still stuck at how to make a Linksys 3102 work OK with the free Axon PBX for Windows*... I was wondering if it's possible to configure the 3012 (or the GrandStream HT-488 that I also have) to have it ring an SIP phone directly, ie. no need for either an SIP PBX or some VoIP account on the Net? For single use, that would solve the issue.

Thank you!

  • that stupid thing goes off-hook when forwarding incoming PSTN calls to the PBX, regardless of whether an extension does ultimately pick up the call
Reply to
Vincent Delporte
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it would seem it is possible, although I've never tried.

I'm not sure about going off-hook immediately; registering the SPA-3000 on Asterisk it's definitely possible to avoid that problem, as explained at

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. Perhaps that can be adapted to the Axon PBX, of which I know nothing.


Reply to
Enzo Michelangeli

Thanks for the link. I'll check it out. It's always nice to keep something as basic as possible.

A sharp-eyed Axon user noticed that, by default, it's supposed to play on-hold music (I hear silence) instead of just keep RINGing the remote extension. Changing that setting solved that issue

But I'm still stuck with the internal softphone's microphone not being hear by the remote PSTN caller, although it works find PSTN ->

softphone. I know just about nothing about SIP or RTP, so it might be something obvious. Actually, that may also explain why I got no music on hold before..

For the curious out there, here's the output of an incoming PSTN call getting into the Linksys, being forwarded from FXS to FXO (at least, that's how I think of it), RINGing extension 101 (a softphone) through the Axon IP PBX, having a (one-way,sigh) conversation, and then finally hanging up:

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If anyone has any hint about why RTP data only seem to travel PSTN ->

softphone but not the other way around, I'm all ears :-)

Thank you.

Reply to
Vincent Delporte

Uhm, I confess I haven't studied the log with the care it would require. To save me time, can you please detail all the IP addresses of softphone, Axon IP PBX, Sipura 3102 (is it ?), router, any third party (e.g., provider proxies) in the piture...

In particular, which piece of equipment has the routable IP adress "" that appears in the log at one point? Have you perhaps enabled STUN support on the SPA-3102, and, as a consequence, is the latter telling the softphone to send its RTP data to the external IP address of the router rather than the internal IP address of the SPA-3102? This would be fine for peers on the Internet, but if the softphone is on the same LAN, it'll never work...

From what I can see, there are a couple of things I don't like very much:

- The IP address (i.e. localhost) being used in several places of the SIP/SDP dialogue. This is an address that only works for interprocess communications on the same host.

- The absence of a trailing ";rport" parameter on the SIP "Via:" headers, which means "no support for

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" and therefore "likely problems with NAT traversal".

Also, I can't see and SIP message referring to an extension 101... And why do you do an "FXS to FXO" forwarding? I thought you were trying to receive a call on the FXO interface and ring a softphone, without involving the FXS interface at all...

Cheers --


Reply to
Enzo Michelangeli

Sorry. I wish I understood what the logs say, and just keep the relevant part instead of just dumping this massive piece of stuff...

The softphone and the Axon PBX are both running on the same W2003 Server test host with IP = The Linksys is connected to the same switch with IP =, with no software firewall between the two (I checked in Control Panel, and W2003 doesn't seem to have a software firewall like XP). I call into the Linksys from a regular analog landline, the Linksys sends an SIP message to Axon, which looks up the extension, makes it ring, I pick up the call : I can hear the remote PSTN caller, but he can't hear me.


- Skype works fine, so I guess the sound card is full-duplex (picked up that bit from the FAQ on SJphone's site

- I guess the same issue with a GrandStream BudgeTone 100 (model 101)

- SJPhone is actually worse than X-Lite 3, as the former doesn't do sound either way.

It's the dynamic IP assigner to the ADSL modem.

I barely know what STUN does, so haven't touched this. By default, Voice > SIP > NAT Support Parameters > STUN Enable = No, and STUN Server is empty.

I do, but the only way I could get the Linksys to notify the Axon PBX of an incoming call is by doing this:

- PSTN Line > PSTN Ring Thru Line 1 = yes

- User 1 > Call Forward Settings > Cfwd All Dest = fxo (where "fxo" is the account used by the Linksys to register with Axon in the "External line" section)

But maybe this is totally not the way to set it up, in which case, what else can I try? Incidently, since I only want to ring a single remote phone, I guess I could remove the Axon PBX from the equation, and just tell the Linksys to hit the phone's static IP through the Net directly?

Like you, I suspect that it's sending its RTP data elsewhere, or maybe the issue is due to the fact that I don't use the FXS and expect data to flow between the FXO and an SIP phone? I doubt it's codec (they use G711u by default) or RTP ports (no firewall).

Is there an IRC channel somewhere where I could ask the experts?

Thank you.

Reply to
Vincent Delporte Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.