DrayTek SIP SoftPhone is described as 'The DrayTek Softphone is a SIP phone in software which runs on any Windows PC. It provides full VoIP connectvity directly to the DrayTEL SIP service or can act as an extension to a DrayTek PBX' and is an app in the Social & Communications category. There are more than 10 alternatives to DrayTek SIP SoftPhone for a variety of platforms, including Windows, Linux, Mac, Android and iPhone. The best alternative is Jitsi, which is both free and Open Source. Other great apps like DrayTek SIP SoftPhone are Linphone (Free, Open Source), MicroSIP (Free, Open Source), 3CX Phone System (Freemium) and Telephone (Freemium, Open Source).
Jitsi (previously SIP Communicator) is an audio/video and chat communicator with full encryption that supports protocols such as SIP, XMPP/Jabber, ICQ/AIM, Windows Live, Yahoo!, GTalk/Hangouts extensions, as well as OTR, ZRTP, etc.
Linphone is one of the most famous open source softphones in the world. It is fully SIP-based, for all calling, presence and IM features. Use Linphone for free, and enjoy its intuitive interface and advanced features with our free SIP service or with an existing SIP account.
Telephone allows you to make phone calls over the Internet or your company network. If your phone line supports SIP protocol, you can use it on your Mac instead of a physical phone anywhere you have a decent network connection.
FreeSWITCH is a scalable open source cross-platform telephony platform designed to route and interconnect popular communication protocols using audio, video, text or any other form of media. It was created in 2006 to fill the void left by proprietary commercial solutions.
Softphone for VoIP, CAPI und TAPI. This application enables voice connections to landline, cellular network and VoIP. Phoner can be used as softphone on stationary and mobilecomputer devices attached to anlogue or digital (ISDN) subscriber lines and as SIP client.