Hi
Once you have qualified your account by sending us your ID and a picture of your credit card, we allow you to manipulate your caller ID any way you want to - you can set it to anything valid, at anytime.
However, the terms and conditions of service say that you must be entitled to send that caller ID. e.g you should not use it to spoof the caller ID and pretend to be someone you are not.
So in a professional installation, I usually set the caller ID to whatever the customer's existing published telephone number is on their landlines, and they continue to recieve calls on the landlines, but when they call out, it goes out via VoIP, falling onto the landlines if VoIP is unavailable (e.g. no broadband, or exceeded the number of concurrent calls on a trunk) but always delivering the correct caller ID of the companies landline.
You set the caller ID in FreePBX, either against the extension or against the trunk.
Yes, there is no reason why you should not set up different trunks all with the same credentials all on the same box, each with a separate callerID to be delivered, and use outbound routes to select which caller ID you send.
Or you could simply set the caller ID on an extension by extension basis.
If you purchase a DID from us, you will require a separate registration per PiaF server, so we know where to send the incoming call. But, multiple DID can be sent out to one registration, and you sort out what to do with them with your inbound routes in FreePBX.
The minutes can all be charged to one account. This is set up manually on request.
This also means that if someone calls you after hours, and you have a follow on system for out of hours calls, say to your Cell phone, the caller ID of the calling person will be delivered all the way through your PBX and appear on your cellphone.
I hope that this clarifies the situation. In a professional environment, I think it is absolutely necessary to be able to set the correct caller ID on a call by call basis, by extension or by trunk, and is a powerful selling point of the service.
Joe