Softphone is the short term for software telephone. It is a computer program that models the traditional telephone set and a software solution with which you can make telephone calls through the Internet using the Voice over IP protocol. Ozeki VoIP SIP SDK provides fantastic technology for softphone development.
The first step of entering the VoIP world is to have a SIP account that will identify you similarly to phone numbers in case of traditional telephoning.
You can easily handle SIP accounts with Ozeki VoIP SDK.