Acrobits Softphone
Acrobits Softphone is a VoIP client which uses Session Initiation Protocol, developed by Acrobits, a software development company based in Prague, Czech Republic. Acrobits Softphone is the leading SIP Client on the App Store, featuring push notifications and the G.729 Annex A audio codec, multitasking, Google Voice integration and encrytped calls through ZRTP.[1]
History
The first version of Acrobits Softphone was released on the App Store in April 2009. Version 1.0 supported only a single SIP account and the G711 and GSM codecs. During the following months new updates were released rapidly, adding new features, and the app quickly became the most downloaded paid SIP app for iOS worldwide. Support for push notifications for incoming calls was added to Softphone in September 2009, shortly after push notifications were introduced in iOS3. The G729 codec was added in Apr 2010. In August 2010, a business-caliber version of Softphone called Groundwire was released on the App Store, adding support for conferencing, voicemail, call transfers, call forwarding and other advanced features of business-grade phones.
With the release of Groundwire, the app reached the level of maturity and completeness and attracted lots of interest from VoIP providers, who asked for white-label versions of the app, optimized and fine-tuned for their network only. Until now, around 50 different white-label versions were created. (apps by Acrobits in App Store).
Later, the following features were added to Softphone: ZRTP support (December 2010), NAT Bridge to help NAT traversal in difficult networking conditions (July 2011), support for video calls (Dec 2011), support for ICE (Mar 2012)
Acrobits Softphone for Android was released in Feb 2011, followed by Android Groundwire in Apr 2012. Android apps are now on par with their iOS counterparts, with the exception of video calls which are not yet supported on Android.
Features
Acrobits Softphone and especially Groundwire support all features and technologies expected in the modern SIP client, plus some unique features described below.
Push Notifications for Incoming Calls
The challenge with VoIP on mobile devices is to make sure that the device is ready to receive incoming calls while keeping the power consumption as little as possible. Due to the inherent mobility of mobile devices, the network conditions change often and frequent SIP re-registrations and keep-alive traffic are needed to make sure the mobile client is properly registered and will receive incoming call at all times. This has a significant impact on battery life.
Acrobits Softphone uses a proprietary SIP Instance Server (SIPIS) to register on behalf of user when the mobile app is not running in foreground on the mobile device. As soon as the app is suspended to background or exited completely, SIPIS server takes over, registers the account and starts listening to incoming calls. When a call arrives, the mobile app is woken up using Apple Push Notification Service (APNS) and the call is handed over to the mobile app.
The advantage of this solution is that the mobile app does not need to run at all on the device, consuming no additional battery power at all, and still be able to receive incoming calls. The media of the call (audio and video) are still transferred directly to the mobile app, for lowest latency and security - no extra relaying is done. Using push notifications doesn't require any support on the SIP server side and uses only SIP protocol standard.
An important point and a potential drawback of this solution is the need to transfer full SIP account credentials to SIPIS server, which needs them to be able to register, which is an obvious security risk. One way to avoid it is to install the SIPIS server on the premises of VoIP service provider, in which case the security risk is eliminated - the provider already knows the passwords anyway.
The service is currently only available for iOS, Android implementation using Google Cloud Messaging is expected before the end 2012.
Secure Calls
Acrobits Softphone supports encrypted voice and video calls using SRTP/SDES as well as the latest ZRTP standard.
See also
External links
Acrobits website
Review from brighthub.com
Review from onSIP.com
Review from bestappsite.com
Review from osnews.com
References
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