Call forwarding to GSM and CLI

I’m very new to all this so please be gentle with me!

I currently use a call forwarding service that receives calls to a virtual geographic number (my published business number), and forwards them onto my mobile, so I can answer my customers where ever I am. This service passes the on CLI from the originator, so I can see exactly who is calling.

I would like to use asterisk to replicate this facility add more functionality (an ip based pbx with several extensions through my premises), so that I can serve my customers better. I’ve got the theory sorted in my head, and I think it is achievable with asterisk - firstly I want asterisk to receive the incoming call (which will probably come in on a sip or iax trunk, along with possibly a single PSTN). Ideally I need it to answer and play a welcome message, before ringing the local voip handsets (possibly with some options - press 1 for X, press 2 for Y etc). If there is no answer on the local voip, I would like asterisk to forward the call onto my mobile phone via a GSM gateway (I have a Dinstar DWG2000).

But one big stumbling block (that might be a show stopper) in my mind, is passing on the originators CLI via the GSM gateway. Somehow I doubt that the Dinstar can do this - surely the network operator will use the GSM sim’s assigned number, and this is all I will see on my phone. So I will know that it’s a forwarded call, but can’t see who it is forward from? If I miss the call, and they don’t leave a message, I won’t be able to see their number to call them back.

Is my thinking correct on this? If it isn’t the case, then people would be malicously spoofing CLI all over the place. What, if any, work arounds are there that asterisk could handle? My first thoughts are putting the caller on hold while I answer the call and get asterisk to play a recording (or generate speech) to talk me the callers name or number. Is this practical or achieveable? The only other thing I can think of is to get asterisk to send an SMS with the callers number, but this would obviously be too slow to allow me to see who is calling before I answer.

Are there any other, more elegant/practical solutions, or am I stuck with using a voip service provider to achieve the cli forwarding? It must be possible as they are doing it themselves somehow. I am in the UK, in case that makes any difference?

I don’t believe any mobile operator will permit this. Some VoIP operators do, but the better ones would ask you to prove that you control all of the phones whose CLID you are generating.

There are VoIP services, although I don’t know who they are and where they are based, that are not as scrupulous, as I get junk calls with impossible CLID values, and the general feeling is that these get round the UK boundary block on foreign CLID by using VoIP.

Yes you can put on hold the person while you receive the fwd call, and also when you have the call you can hear their name or their number, this is a common config called: call screening.

Hi all…
I am new to asterisk…can anyone tell how to forward a call to external number…

actually I have written an IVR. So when the call will come to IVR…there is one option to go to Tech Support. So when the caller will choose that option … the call should go to that Tech Support number…

pankajthakur: You also seem to be new to forums, as you have tail ended an unrelated thread.

Dial (//)

depends on the technology and, in some cases, on specific options for that technology. There are alternative syntaxes.

Hi David

I used the same syntax Dial(SIP/9852xxxxxx/9853xxxxxx), but not able to forward the call.
When I am registering the soft phone with 9852xxxxxx(DID number) and calling to IVR, at that time I am able to transfer the call to 9853xxxxxx(external number) from the IVR. But when I am registering the soft phone with any other number, then I am not able to transfer the call.