[bbob]

Many years ago I did have a windows based callback server. Only problem was that it only worked thru analog or isdn lines. I had a isdn card in my server, called my isdn number go busy tone and the software would call me back thru the isdn line. I would than get a dialtone and would call out on the second isdn channel.

This was still in the days that lichtenstein numbers were cheap to call.

I tried at that point to get if working thru voip and could only do that by hooking up the isdn card to a fritzbox voip modem. So yes you can do it but you need a good isdn card and it might be easier setting up a small asterisk based sever.

So far I did not find any dedicated windows based callback software that works with voip. asterrisk for windows does not support it, axon antoher windows based pbx does not support callback, 3cx also windows based no callback.

Your link looks nice but as far as I can see there is only 1 voip provider you can use. So that voip provider must supply you the incomming did number and you also have to use it for outgoing calls. This makes you depend on 1 voip provider. But maybe you can use a betamax brand that still has an incoming number with the account, than it might work.

Other thing I don't know if you can add more than 1 callback number if not you would have to use the did number only for callback.