Vonage to Asterisk and empty voicemail

Hi All,

I’m pretty new to Asterisk and have pretty much setup the box and it has been running well except that on occasion I have been getting ‘empty’ voicemails from my Vonage account.

The setup that I have is

Vonage box --> TDM400 -->asterisk box

The system works great for calls coming in and out etc but i get these voicemails that always run for 34 or 35 seconds and have a dialtone for 6 seconds followed by a busy tone.

I don’t know a lot about all of the configs but I had assumed that because the Vonage box is setup to work in the US and the default settings for Asterisk ‘should’ match it, I have not changed any of the line level settings etc.

I have been able to reproduce the problem by letting the call go to voicemail and then hanging up just before the voicemail greeting has finished.

I guess my question is: Is there any way to stop voicemails being sent if all they contain is a dailtone followed by a busy tone?!

I have put one of the VM’s that ive been getting on the net if it helps




What does Asterisk do when a call comes in? What (you think) is it doing when the call hits voice mail?

Empty voice mails are unavoidable. But as you indicated, you can reproduce this by hanging up (the calling party, not Asterisk, I assume). I bet that even without Asterisk, you can reproduce the same using exactly the same method.

I think what is happening is that because of delays between when the caller hangs up, vonage knowing that the user has hung up, and the TDM400 card detecting that the vonage has hung up etc means that if the caller hangs up within a couple of seconds of the end of the voicemail greeting the system thinks that they are still on the line and starts recording the call. But by this time there is no one there so instead the line (vonage box) just gives a dialtone (as if calling out) and then times out giving a busy tone.

The messages themselves are not empty per se… they all have a length of about 33-35 seconds which I am assuming is the time in which asterisk works out that there isn’t anyone there.

I have tried reproducing the issue without the asterisk system in the loop by just connecting a telephone directly to the vonage box and letting vonages vm pick up but the problem does not present when doing this.



OK that is a fact of life with this homebrew setup.

You will always have that delay as there is a added step when you are using the Zaptel cards.

BUT there should be some silense detect going on I would think 5 second would be the cut off not 35 seconds

My 2cents is to use other providers such as broadvoice.com (BYOD; bring your own device) or connect.voicepulse.com (for asterisk). Vonage is not suitable for anything that has to do with asterisk or config setups unless you enjoy having issues or not being able to accomplish your goals at all.

agree w/ uno. ATA to FXO port is a lame setup, you will be much happier with another provider. You might also try Viatalk.com, they don’t suck from what i’ve seen.

However with your existing setup if you want to try and fix it- in zapata.conf try turning on disconnect supervision. If that does nothing, call vonage and ask them to enable disconnect supervision.

Disconnect supervision means that when the remote end hangs up, a CPC (momentary polarity reversal) is sent by the ATA on the analog line. An easy way to test this is plug in a simple phone with a light up keypad (the kind that’s powered by the line, not a battery). Call your cell phone, and then hang up the cell phone. If the keypad goes dark for a second, that’s a CPC.

Thanks for the suggestions guys… I’ll give them a go and see what happens.

Unfortunately the current situation was forced on me. The numbers connected to Vonage account have been distributed on promo material so can’t be changed and since Vonage wont allow me to change to a std direct trunk connection i’m pretty much stuck with it :-/ I guess thats what happens when marketing controls IT :frowning:

actually you can port a number out of vonage to a carrier like viatalk or broadvoice that will let you byod. Not all carriers can port all numbers, although if the carrier offers numbers in the same prefix (111.222.nnnn) you can be almost sure they can.

Just sign up with the new carrier and tell them to port your number, fax them the form and see what happens. If vonage gives you any trouble, email portout@vonage.com

Also, of course do not call vonage until after the port completes.

However after you do port you will have to call vonage and cancel. As well as cancelling, tell them you’ve ported your number out and you need them to remove it from their database. If the guy goes ‘durrrrrrr…’ just tell them to submit a level 3 ticket called ‘remove DID from database’ and put your number in it along with a note that it’d been ported out. That will save you a 45minute wait for tier2 support.

If you don’t do the above, Vonage may think they still have the number. This means Vonage users who call you get an error msg, everybody else gets through. Or worse they will assign it to somebody else, which means Vonage users who call get him but everybody else gets you.

The Vonage box doesn’t do the recording. It’s the Vonage side that does this. That’s why it’s strange that you couldn’t reproduce this with a plain phone at the ATA.

caller -> Vonage termination -> Internet -> your ATA -> Asterisk ^ Vonage voice mail

Put it this way, just like there’s no way to know if the other side of the Internet is a dog or human, there’s no way for Vonage to know that you have Asterisk instead of a plain old telephone. Obviously your Asterisk hasn’t picked up the line or Vonage shouldn’t start voice mail. Is this right?

What (I would imagine) happened was that the caller hung up too close to announcement’s end; for some reason Vonage did not detect line hang-up. This always happens in your home recorder, right? But shouldn’t happen to Vonage, who uses PRI at minimum. Or Vonage voice mail just ignored line hang-up condition. Any way, Vonage voice mail started recording. By this time, Vonage’s telco started to send dial tone, hence the dial tone recorded. After 30-35 sec., Vonage’s telco detected that Vonage’s termination hadn’t hung up, thus sent this busy signal before dropping the line dead. (Hence the busy.) Vonage either detected fast busy or got this dead line condition and hung up, stopped recording. Hence the 30-35 sec. 30-35 sec is about right for a telco to start sending fast busy, but it usually drops line longer after.

How close to the end of voice mail prompt you must be to reproduce this?

Some news article talked about difficulty to transfer a number out from Vonage years ago. Do they still not allow transfer?

as i understood it he plugged his ATA into an FXO port, and is having trouble with asterisk voicemail (which would make sense). If he was having trouble with vonage’s voicemail system he should call Vonage…

If it’s the Asterisk voice mail, then sounds like a typical disconnect supervision issue. Unless Vonage provides it, you can’t do much about this.

However, my WRTP54G seems to work fine with TDM400P’s FXO. (Haven’t really tested voice mail on Asterisk, but disconnect is detected fairly accurately when I use fxs_ks.) So I believe that Vonage does provide this to end user. Maybe the very ATA model doesn’t support this feature.

I think there is a bit of misunderstanding here valley… The problem I am having is with my voicemail (on asterisk). The vonage vm works just fine…

I tried doing as suggested and tried a couple of the different methods suggested on asteriskguru but without much luck. I already had the signaling set to fxs_ks and also turned on hanguponpolarityswitch but no go. Unfortunately I don’t have a telephone that is non-powered so I cant test whether polarity reversal is enabled. I will have a chat with Vonage and see if they can confirm this.

asteriskguru.com/tutorials/r … email.html

I just spent 45 minutes of my life that I will never get back talking to Vonage ‘technical support’… HOPELESS!

At the end of the conversation he just ended up saying that they couldnt do anything on their end :confused:

Thanks for your help guys…


their tech support are morons. Port your number to a carrier that supports BYOD, like viatalk or broadvoice and the issue will go away.

Usually I’d suggest try another ATA. But because Vonage locks all ATA’s in, it’s generally not worth it.