Question about DISA & Voip


i’m interested in setting up an asterisk box, especially for use with mobiles.
Is the following setup possible:

my mobile dials my asterisk box, which does’nt answer (so i don’t get billed).
then * calls me back thru a voip provider, giving me a dial tone.

Now my question:

let’s say my voip provider gives me free rates to landlines in this or that country.
When * gives me the dialtone to my mobile, shall i get billed just for the time of the connection (i.e. a few seconds), or shall i get billed for all of the duration of the call, accumulating the (voip)rate of * > my GSM and then my GSM > the landline?

yes. you shall get bill all the duratoin, because you need to input destination number. there is an application named callback. you could find many softswitch support it.

If your provider doesn’t charge for local calls, and your cellular is considered local for the callback, and the destination where you will call with disa via asterisk is also local, you’ll not get charged.

As long as your provider does support at least 2 simultaneous calls with your account as your call will be 2 way.

i’m afraid i’m on prepaid cards, so i pay everything.

i would like to know what’s the most economic way of having asterisk doing a callback to my mobile.

If i let * hang up when i call it thru my GSM and let it call me back with a SIP provider, i pay both the call asterisk > GSM + the call itself i intended to have for all of the duration of the call. Is that right?

Could i access the asterisk server on a web page, asking for initiating the call trhu a SIP provider? I pay 0,015 € / ko. The moment * passes me the dialtone over the GSM network, my data web connection stops right?

Or could * hand me the dial tone thru SMS? That should be cheaper, as the SMS is billed only once?

Or maybe it’s cheaper having a dedicated VOIP DID number?

thanks for any help

Most likely would be a 2 legs call, so you will pay for both connections.

(One from Asterisk to Your Cell using Your VoIP Provider, One from Your Asterisk to your Destination using your VoIP provider = 2 Calls).

ok thanks,

but how about some practical suggestions?

ok thanks,

but how about some practical suggestions?

I’ve always paid for 2 calls when I use my call back personally.

For example, now i’m in Mexico for Work. I’ve a Mexican Cell phone and an American DID. I call the american did which never answers. The system call me back on my cell phone… .

From now on, you have 1 Call going on at your provider, Asterisk -> Your Provider -> Cell Phone…

Now I dial an American number. Asterisk dial via your provider to your destination.

There’s no way to drop the initial call between your provider and your cell.

Get an FXO Card or a provider with flat monthly rate if per-minute is so expensive for you.

ok, this is clear.
could this be done thru SMS?

What would be the advantage of using SMS? You pay for it and you have to build an application that receives it and uses it to set up the call for you. A short “setup call” is probably cheaper and much easier (one touch dialing).

Ever considered SIM-gateways? They allow you to call SIM-SIM via a flat rate. There should even be a SIM-SIP gateway (don’t have details for you, sorry) that can do the dial back to your GSM.

Be careful when you bridge 2 calls in your Asterisk box: I experienced that SIP hangup is not detected properly so that the calls last longer than you want (see … teway.html

well, i pay 0,09 € for an SMS but a lot more for a call to a GSM.
As giving a dialtone results in a two-leg call both being billed until the GSM hangs up, that seems quite expensive to me.

With an SMS, it would be a “one time” billing, just the price of the SMS, no?

I wonder whether it would be easier to reach the asterisk server on a web page on 3G with the URL having the number i wanna dial. Would that be possible?


What country do you live in, what are the “traffic rules” there and what is your business case? I am surprised to hear about a country where a SMS is cheaper that a short GSM call!

I assumed that you live in a country where inbound calls to your GSM are paid by the caller, outbound calls from your GSM by you and both on a per minute (sec) basis for a relatively high tariff. I also assumed that your business case is to lower the cost on your GSM bill.

So what you probably want to do is to set up calls to your GSM instead of from your GSM, because the inbound tariff is so much lower than the outbound tariff that it is worth the effort. If you can’t solve it with the standard callback/bridging functionalities I would not advise you to make it even more complex with SMS or web!