How to forward to an extension at an outside phone number?

I need to forward calls to an extension at another number. I have tried a few different ideas with no success. All assistance is appreciated.

Easiest is to use follow me and put that other # in and remove the ext.

Or just use the call forward feature… Or make a ring group and put the external DID ( I assume) in the group like 13334445555# and not that the # sign indicates an outside number to call.

I have that part and use it.

Here is what I am having an issue with. I forward to an outside line, but once that line picks up I need to enter the proper extension. On some systems you use commas to create a pause, but trying that here did not work.


I wish to forward to 1-888-555-1234 x101

I tried to use 18885551234,101#

The system removed the commas and the forward did not reach the desired extension.

Since this must be a common need, I’m sure there is a answer. Any ideas?

Try creating a custom extension. In the custom dial box, dial out using you outgoing trunk. I have ZAP trunks, so my outbound dial looks something like this:


6016361053 is the inbound number.
the w’s are waits 500 ms each
203 is the extension number.

The exact format will vary depending on what type trunks you are using.

HINT: you can get an idea of your outbound dial format by bringing up the asterisk CLI, dialing a number and watching for the dial command.


I’m trying to do this from the extensions follow me list. I tried the wwww to create a wait until the extension is dialed, but upon applying it, the system strips out the w’s.

Any other ideas?

Once you’ve created the custom extension, you can use it just like any other extension…including a follow me target.

Ok I have a SIP trunk. So with that what would the virtual extension look like if I wanted to dial 123-456-7890 ext 500



Bring up the asterisk CLI with 3 v’s. Dial an outside number and see if you can pick up the command your system is using to dial.

It will look similar to the ZAP dial sequence I described earlier with

If you dial 601 555 1212 it should look something like…

SIP/TRUNK ID/6015551212

The ‘TRUNK ID’ portion will be the name of your outbound trunk.

You’ll use this syntax in the custom dial sequence replacing the 6015551212 number with the external number of the other switch andon with the waits and then the extension number. You may have to diddle with the number of w’s so it works as transparently as possible.


This is helpful. So now since it is a SIP trunk when I go to add an extension is it a Generic SIP Device or is it a Virtual Extension? and then once in the configuration screen of this new extension, which field do I enter the SIP/TRUNK ID/1234567890

Thanks for the assistance,


Custom Extension. I think that’s the only way you can add a custom dial command.


Ok and into which field does the dial string go?



In the “Custom Extension” setup page, about halfway down, you’ll find a box that says something like “this device uses custom technology”. That’s where you place the dial string.


Getting closer. I watched to outbound string and the last letter of the name changes. I now get a ring when I dial the extension, but it is not forwarding. I used:


when watching the system make calls the last letter changed each time on 3 calls from b to d to f. I tried the name with and without the last 2 letters with the same results. Also tried it with no letters at the end, same results. The number just rings and eventual hangs up. If I use just the name without the “-000025bb” it rings once then a fast busy tone.

Thanks for assisting a noob.

Make sure you put thewaits between the number and the extension.

I did and I also tried a direct dial to my cell just to test the string and it did not make it to my cell. Just rand for a while then hing up.

What do you see in the CLI when you dial a number manually? That string is what you should be trying to emulate for the automatic forwarding…