GO HERE Cisco 7940

Tobyl

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I have happened upon a Cisco 7940 IP phone an have successfully flashed it to the SIP firmware provided by Cisco.

I have tried to register the phone with an Asterisk (1.8.28.0) server running PIAF from another location, over the WAN. I have opened ports at both the server side and the phone side, and I can make other SIP devices register with the server from the same network as the 7940.
The Asterisk server is showing the phone as offline and any calls to the 7940 go straight to voicemail; "the person at extension XXX is unavailable".

I have watched every YouTube video on the topic and changed many settings to and fro, yet cannot make the phone register or receive calls. Interestingly though, I can make calls from the phone to another, and the receiving phone does show the correct extension number and display name of the 7940.

What is the problem? Why does the phone blatantly refuse to register? The asterisk log file doesn't even show anything useful. I am tearing my hair out...

Thank you very much in advance!!!
 

rossiv

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I tried for a long long time to get a 7970 to register over a Wan connection through NAT and never had any luck. Even giving the phone a public IP didn't work either.
 

Tobyl

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You're not filling me with confidence :)
If there's any news I'll let you know if you like...
 

rossiv

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Sorry bout that. :) I have since given up on Cisco 79XX phones and moved on to Snom and Mitel as my primary vendors.
There is someone else here that did a big writeup on 79XX phones. I feel like it's snarpatroid. Probably spelled that wrong since I'm on mobile but perhaps he will have more insight than myself.
 

Jake

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I've had the same troubles. It seems to me Cisco phones hate anything to do with NAT. Your best bet might be a VPN tunnel between the sites.
 

Tobyl

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Sorry bout that. :) I have since given up on Cisco 79XX phones and moved on to Snom and Mitel as my primary vendors.
There is someone else here that did a big writeup on 79XX phones. I feel like it's snarpatroid. Probably spelled that wrong since I'm on mobile but perhaps he will have more insight than myself.

Thanks for that, I'll give that a look.

I'll read this as well, looks very interesting, thank you.

I've had the same troubles. It seems to me Cisco phones hate anything to do with NAT. Your best bet might be a VPN tunnel between the sites.

I have looked into VPN, and I agree, it looks like this may be my only option.
 

Jake

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I've loved my PfSense firewalls with OpenVPN SSL tunnels.
 
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Hi Tobyl the fact you can make calls but not receive them seems to indicate to me there's a registration problem. I would start by checking you have ports 5060 and 5061 enabled. Next I would be looking at STUN. I would also check to ensure the handsets are using TCP not UDP.

See how you get on with those tips. Good luck.
 

Tobyl

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I've loved my PfSense firewalls with OpenVPN SSL tunnels.

Thanks for the advice, I will bear that in mind.

Hi Tobyl the fact you can make calls but not receive them seems to indicate to me there's a registration problem. I would start by checking you have ports 5060 and 5061 enabled. Next I would be looking at STUN. I would also check to ensure the handsets are using TCP not UDP.

See how you get on with those tips. Good luck.

I thank you greatly for these tips. I will try them tomorrow when I have some time and will return with the results. Thanks again!
 

Tobyl

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Thanks for your help snarpatroid but according to Cisco, the 7940 doesn't support STUN, however I have set the public IP for the phone in the NAT address configuration and enabled it. Cisco also say that it doesn't support TCP for voice transmission. I have enabled port 5061, which I had not earlier, but this has had no effect.
I do not see a logical reason for this upset?
 

Tobyl

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And sorry that took so long, some unexpected and very annoying things came up for me to deal with! :banghead:
 
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I am not too hot on the 7940 (get yourself a 7941 and I've pretty much wrote the book on these though!). Others have had more luck with IAX rather than SIP transport so that might be an option? If it is just this one handset you need the 7941's are cheap as chips on ebay right now.
 

Tobyl

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Thanks for that, I may take you up on that offer of help!! (If I get a 7941 instead, I suppose newer is better...)
 
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It's not really a case of newer being better, more the 7941 and 7942 use totally different ways to configure these handsets than the 7940's, are on much more recent firmware and work with TCP as standard on their latest firmware. The 7940's in comparison only do SIP to the extent Cisco implement it to be able to say they support SIP, practically they might as well start shouting out they don't give two hoots about SIP on the 7940 (as unfortunately you're finding out).
 

rjaiswal

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If you really want to use the 7940, you could try running it with chan-sccp...
 

Tobyl

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It's not really a case of newer being better, more the 7941 and 7942 use totally different ways to configure these handsets than the 7940's, are on much more recent firmware and work with TCP as standard on their latest firmware. The 7940's in comparison only do SIP to the extent Cisco implement it to be able to say they support SIP, practically they might as well start shouting out they don't give two hoots about SIP on the 7940 (as unfortunately you're finding out).

I agree totally.

If you really want to use the 7940, you could try running it with chan-sccp...

I had heard about this, but also the fact that it is challenging to install?
 

rjaiswal

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It's not too difficult. There is a forum post I did awhile ago with the proper XML files and instructions on how to compile.

That's how I'm using the 7940's I acquired from a large chain of music stores that went out of business in NYC. :)

The sip firmware on them was horrible....

I'm typing this on my IPad, so I can't link the post... :-(
 

Tobyl

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rjaiswal No worries! :) I'll poke my nose in today and see what I can find. Thank you!
 

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