Dial a Number Before Connecting the call

Asterisk Asterisk Support
1

Hi Guys,
Im setting up a Overseas Calling Facility, in general to connect the call a number needs to be called first, it is a toll free number but unless it is dialled they cant call abroad.

How would i set asterisk up so it calls that number before it passes on the number the person has dialled?

2

Why does not simply prefixing the number not work?

Either the problem is trivial, or you have not fully specified it.

3

I think David is correct. You should do something like this
exten => s,1,Dial(DAHDI/1/18005551212w${EXTEN}

This will prepend your 800 number to the dialed number