I have a laptop with a static ip and with a USB Modem w/ simcard connected, i can do voice call locally. I am looking for a solution if its possible for me to place an IP call thru my laptop , thereby using the USB modem connected to place the calls.
Additional info my laptop is connected to the net via DSL connection
Thanks for your comment, i have already use skype and that is not what this topic is incline to, i do lots of traveling and i would want to be able to connect to my own modem with sim to do the calls, since in the first place the laptop has a static ip address
If you have a home phone line, you can setup a trixbox or other asterisk based system and connect your laptop via a SIP trunk back to the trixbox to make calls using your existing home phone without having to pay for any extra monthly fees. If you don't have (or don't want to have) a home phone line, you would have to get a SIP trunk from a provider and pay the monthly fee for that. There are some free ones out there, but they are very limited in what they can do and numbers they can call and typically charge for most calls.
i have one similar setup like that in my office, i want to use the usb modem w/ simcard for its mobility purposes. because the modem can be use for calling locally, i just want to TRY to use it over ip as an experiment
For testing purposes, one of the free SIP providers may work just fine. The only thing in addition to that that you will need would be a softphone. In my experience, X-Lite is pretty simple and free. http://www.counterpath.net/x-lite.html