Archive for the 'Fax over IP' Category

Fax over IP: How does it really work?

Friday, September 22nd, 2006 by Martin Cadirola

Fax over IP is one of the great features of Kapanga Softphone. From time to time, our prospects asks us about what actual benefit our implementation of Fax over IP brings to the table. Our answer is simple: reliability.

There are two ways of sending faxes over IP; one is transporting the fax tones over RTP (Real-Time Transport Protocol) just like plugging your standard fax machine to the ATA device from your provider; the other is transporting the binary information the fax tones carry using IFP (Internet Fax Protocol). The latter method is standardized by the International Telecommunications Union (ITU) under the T.38 specification. We at Kapanga Softphone implemented T.38 support and built it into the softphone.

Why is then T.38 the recommended way to send faxes over IP? Here are a few key reasons:

1. Transporting fax tones (and tones in general) over RTP is unreliable when using voice low bit rate codecs. In other words, sending a fax using G.723 is virtually impossible due to the distortion introduced by the transcoding.

2. When a fax is traveling through RTP, even the slightest presence of echo prevents the end points from demodulating (=receiving) fax tones correctly.

3. T.38 is the preferred option for end points like softphones and media servers since generating and receiving fax tone signals in audio requires a lot of CPU power.

4. T.38 provides embedded redundancy and error correction methods, resulting in a more reliable way of transmitting fax over IP than RTP.

Thus fax sent using T.38 through an IP network will result in a very reliable solution for both sending and receiving fax .

Advantages of Fax over IP

Tuesday, August 29th, 2006 by Martin Cadirola

A customer of ours sent us a nice article from Computer World about uses of Fax over IP (FoIP). It goes over the basics of FoIP and the advantages of using it with your current VoIP network. We find that most of North American providers however are lagging behind support of FoIP compared to the European or Asian markets. The good news is that Kapanga Softphone is the only SIP client that support Fax over IP! Click here to read the article. You can also try Kapanga for free by downloading a trial here. If you have a favorite VoIP provider, please let us know. Enjoy!

Hello and Welcome!

Wednesday, August 9th, 2006 by Martin Cadirola

Hi there. We’ll be┬áhere blogging about current events in the VoIP world, and also planning on keeping you up-to-date with developments with Kapanga Softphone. We have been posting some news on the Community Forum, and due to customer requests we felt that a lot more people would benefit for having information in this format. Without extending this first entry too much, we want to thank again all users of our product. Stay tuned!