Twinkle Softphone: Review

Twinkle seems to be one of the most ambitious Linux softphones.  This free open source softphone offers voice communications and instant messaging using SIP protocol. Twinkle is one of the most widely used SIP softphones. It’s popularity can be given to the fact that it is available in the stable repos in the main distros (Ubuntu, OpenSuse and Fedora). The VoIP application uses Qt toolkit for its graphical user interface. For calls Twinkle uses the session Initiation Protocol (widely used for controlling multimedia communication sessions such as voice calls over IP). It can be used for straight IP to IP calls as well as in a network using a SIP proxy to route your calls and messages. Let’s delve into its key feature of Twinkle to find out where does it stand in the queue of open source softphones.

Twinkle is easy to build and get it running. Configuring the is simple, but for people with more than one SIP client might have trouble figuring out how to set the default account.

The softphone offers a simple, user-friendly interface. The twinkle interface features buttons for common actions, a pull down list to choose which connection you want to use for a call. It features a input field for typing in the number you would like to call.

Features

To begin let’s deal with some of the basic features

• Supports upto 2 parallel lines
• Multimedia active call identities
• 3 way conference calling
• Inband DTMF
• Out-of-band DTMF
• STUN support for NAT traversal Call redirection unconditional
• Call redirection when busy
• Call redirection no answer
• Reject call redirection request
• Blind call transfer

Security

In Twinkle media streams are transported via Real-time Transport Protocol that may be encrypted with Secure Real-time Transport Protocol (SRTP) and ZRTP security protocols. It has a MD5 digest authentication support for all SIP requests. AKAv1-MD5 digest authentication support for all SIP requests

In addition to these, it also includes identity hiding features.

Audio codecs support

Twinkle supports a wide variety of audio codecs

• G.711 A-law (64 kbps payload, 8 kHz sampling rate)
• G.711 μ-law (64 kbps payload, 8 kHz sampling rate)
• GSM (13 kbps payload, 8 kHz sampling rate)
• iLBC (13.3 or 15.2 kbps payload, 8 kHz sampling rate)
• G.726 (16, 24, 32 or 40 kbps payload, 8 kHz sampling rate)
• Speex narrow band (15.2 kbps payload, 8 kHz sampling rate)
• Speex wide band (28 kbps payload, 16 kHz sampling rate)
• Speex ultra wide band (36 kbps payload, 32 kHz sampling rate)

Preprocessing Options

Twinkle offers preprocessing options to improve the quality of the call that include

• noise reduction
• Automatic gain control  (AGC)
• Voice activity detection(VAD)
• Acoustic echo control (AEC) Experimental

Presence Functionality

Twinkle supports only basic online and offline presence states (PIDF) using a presence agent that must be provided the SIP provider. User’s Buddy list is stored locally on your computer.

Instant Messaging

This is one of the recent additions in Twinkle. The softphone now allows basic instant messaging that includes sending plain text messages. Fuurther, the user can receive plain text or rich text (html) messages.

KDE features

There are some exclusive features for the systems that provide KDE libraries. Twinkle softphone offers

• When someone is calling a balloon popup from system tray
• User can dial phone numbers from the Kaddressbook
• Display names from KAddressBook on incoming calls
• Display photos from KAddressBook on incoming calls

Pros

The positives in Twinkle softphone include

• Integration with KDE’s addressbook
• Easy to configure
• Support for multiple codecs
• Support for multiple accounts
• User can set the audio device used for the incoming call ring-tone separately from the audio devices used for the speaker and microphone for the call.

Cons

Here’s the list of negatives for Twinkle

• It is a straight SIP client that doesn’t support Skype
• No video support
• Fails to shut down properly. To terminate it you might have to use the kill -9 of its PID
• Lacks call recording facilities
• No IM emoticons
• NO support for watcher information
• There might be hassles with QT or KDE on FreeBSD that may not manifest itself on other platforms

Conclusion

Given the host of features Twinkle lacks some of the most frequently used attributes such as voice and video call recording that it needs to improve upon. However, with some upgrades in the version 1.4.2 and a futuristic roadmap Twinkle is fast emerging as one of best SIP softphones for the *nix clones.