No Dial Tone on IP Phones


#1

I have 2 Grandstream IP phones behind a firewall. They can call each other by IP no problem, but when I enable Asterisk, they cannot, and they lose their dial tones.

The Asterisk server can “see” the phones, but lists them as “unmonitored”.

Any ideas?

TIA


#2

What do you mean by “see”? If you’re talking about them coming up in the sip show peers command then that doesn’t mean anything - it only shows you’ve configured them in sip.conf. If they’re not being monitored, Asterisk doesn’t have a clue whether they’re there or not.

I use a BudgeTone, configured to register with Asterisk and configured with qualify=no in sip.conf (as it needs to be). It works perfectly, but i don’t know of any way i can tell from the Asterisk console if it’s actually online or not.

I thought sip show subscriptions showed who’s registered, but it doesn’t in the version i’m running (v1.2 CVS-head).

Can you ping the phones from the Asterisk box?

Are the phones configured to register with Asterisk?

Have you checked /var/log/asterisk/messages to see if there’s any logging info there that might be helpful?

Have you tried turning on debugging on Asterisk to see if that gives any helpful information.

If neither of them help, you may have to use ethereal to monitor what packets are passing back and forth - if any.


#3

When troubleshooting issues like this, it’s helpful to know that the dial tone you hear is coming from the PHONE, not the Asterisk system. (Except in the case of TDM400P analog FXS modules. There, the dial tone is generated by the card in the Asterisk box.)

Most, but not all, VOIP phones will not generate and play dial tone if they have not registered with a VOIP system, or if they have lost their registration. No-dial-tone is a really good, traditional, indication that you can’t make a call. So when you lift the handset, and it’s silent, you should go looking for a problem.

What you’re really troubleshooting is a registration problem. Click here for help with grandstream setups with Asterisk

voip-info.org/wiki/view/Aste … +budgetone


#4

Understood.

Same here.

[quote]
Can you ping the phones from the Asterisk box?[/quote]
Yes.

Yes, in the web page that administers the phone.

I will, thanks.

Yes, if what you mean is setting SIP debug on. Nothing unexpected.

I guess that’s next. But I would expect this to work “out of the box” as is indicated in both books on Aterisk. My ignorance, I guess.


#5

I went here: voip-info.org/wiki/view/Aste … +budgetone
and tried everything short of upgrading the firmware to no avail.

Maybe, but the Grandstream manual describes the LCD display for the Network Status Icon, and it indicates that the SIP server is not found. It is supposed to flash if the phone is not registered properly - at least that’s what the docs say.


#6

This stuff generally does work - so long as it’s properly configured.

Are you saying that the phone is telling you it can’t see the SIP server?

In that case, you will have to check your phone’s configs. Have you configured the SIP server address as a domain name or an IP address? Have you got anything configured as domain names? If so, have you got the DNS settings in the phone configured properly?

Have you got a tftp server configured in the phone? My phone seems to hang before registration if there’s an address for a tftp server but there’s not server there etc. It’s probably a good idea with these phones to have a tftp server running on your local net somewhere (probably on the Asterisk server) but with nothing in it’s public directory (unless you’ve got things you want to put in there, of course). My phone certainly seems to get registered quicker if that’s set up.

This stuff probably isn’t the issue if the phone works ok with another phone though.

What happens when you boot the phone up?

I’ve had a couple of weird periods with my phone - similar to what you’re describing probably. It was kinda like the phone had got confused. It’s only ever happened when something’s changed - never just spontaneously when it’s happily registered. Last time i was pulling my hair out and i went through all the configs and redid them - including stuff on the phone LCD/keypad. Eventually it just started working again.

The annoying thing about configuring this phone is that field in the config web pages come up blank when they’re really configued with something. You can’t see what’s actually configured and it looks like nothing is. To make sure a field’s blank, you should type in some characters and then erase them and then save it. That could be just my web browser(s) (opera and firefox) but i doubt it.


#7

Thanks for bothering with this. To go through this frustration yourself is bad enough, but to offer to help someone else struggle through it is nearing sainthood…
:wink:

[quote]Are you saying that the phone is telling you it can’t see the SIP server? [/quote] Yes. The Grandstream manual describes the LCD display for the Network Status Icon, and it indicates that the SIP server is not found when it is not displayed. It is supposed to flash if the phone is not registered properly and stay solid when connected. Not sure this REALLY matters, but does yours show the Network Status Icon when working properly?

[quote]Have you configured the SIP server address as a domain name or an IP address?[/quote] Yes, an IP address.

[quote]Have you got anything configured as domain names?[/quote] Yes, the same as my router.

[quote]If so, have you got the DNS settings in the phone configured properly?[/quote] Yes, the same as my router.

The phone boots, and the info in the phone matches what is presented in the web page, but the Network Status Icon flashes briefly, then disapears, along with any dial tone.


#8

Mine (a BudgeTone 101) doesn’t have a network status icon - just an icon which tells me if the ethernet is connected or not.

Which model phone is yours?


#9

[quote]Mine (a BudgeTone 101) doesn’t have a network status icon - just an icon which tells me if the ethernet is connected or not. Which model phone is yours?[/quote] It is a 102. The manual calls it a “Network Status Icon” and it flashes whenever you reboot.


#10

Ah, yeah, so it does! I’ve never read the description of that icon in the manual - i thought it was just whether or not the ethernet was connected. It says

What’s you network topography? Are both phones and the Asterisk server on the same subnet?

Have you got a firewall of any sort running on the Asterisk box?

Are both phones set up identically? And do you get exactly the same things happening with both phones?

Are “IP Address”, “subnet mask” and “default router” properly configured on the “Basic Settings” page of the web config of the phone?

Is “SIP Server” properly configured on the “Advanced Settings” page?

Have you tried doing a “Restore Factory Default Setting” (section 8 of manual)?

If not, do it and start the config again from scratch.