问题
I'm interested in building VOIP that actually can be used to call to analog phone using SIP or H.323. But my question is that, is it even possible to build Computer to Phone & Phone to Computer VOIP phone calls with SIP or H.323? Else what is the most common way of achieving this task? I've successfully built an application that i can transfer voices between two computers by using socket, and my guess is that building SIP to communicate with analog phone is quite complicated (even though i read some docs, i still haven't fully understood it) and has a quite different architecture than ordinary socket communication applications. So is it possible to achieve my goal using SIP servlet or H.323? And if you have experienced building it, could u plz share some of references or docs that you have used with me? I would appreciate it so much and I'm pretty sure it will be helpful for all the others who are looking forward to building similar app as mine.
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According to begin with java voip
a dude recommended using APIs like http://public.ifbyphone.com/ or https://www.tropo.com/home.jsp but i have strong feeling that these people will ask me to pay money to use their API, and all i want to do is just build it by myself and try-out only purpose without commercializing it at all. I've found a quite decent VOIP related thingy called VoiceXML, but is it the same kind of API or library as the ones I've mentioned already? What exactly is VoiceXML?
回答1:
You have in fact two questions:
Call a SIP servlet with a softphone. It is quite straightforward to accomplish it via Mobicents/Sailfin. Download any of those and look for a click-to-call example http://www.mobicents.org/facebook-c2c.html. In order to listen for media you will have to use a media server that will send you audio/video to your softphone.
VXML is the scenario that your server will interpret when you call it (think about the menus for online banking, prepaid recharge, etc.). See Voxeo's http://www.vxml.org for details (BTW: you can create an account on their website and test your vxml applications by calling them with skype or SIP( http://www.voxeo.com/developers/evolution-ivr-developer.jsp).
来源：https://stackoverflow.com/questions/11541847/java-sipservlet-to-build-voip-phone-calls-between-computer-and-analog-phone-mob