Softphones Anyone?

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A couple of days ago a friend forwarded me a link to a blog that had postings about the blogger’s (Corey smith) search of the perfect softphone.

What is the challenge finding the right (and cheep) softphone? First let me clarify that at we do not offer a softphone. We may do so in the future but took a decision to delay those efforts in favor of other applications. Stay tuned they are coming soon!

However, we decided to try and address Corey’s questions and Alon wrote an email response that was published in Corey’s blog. Below is that response.

“I want to start by saying that so far Skype outdone all the others in terms of audio quality, even though I believe they have outsourced that technology from a German company at least in their early days. The above means that in spite of what I am going to write, the task of making a good Softphone may not easy but is not impossible.

The problem with a Softphone is that the environment in which it operates if very undefined and with many moving parts. Unknown CPU power, unknown microphone and speaker gain parameters, unknown audio device, unknown audio device drivers, unknown load on the computer CPU at any given moment, unknown amount available memory in the system, unknown internet connection quality, and so on.

Sometimes people don’t even have a microphone on their computer but let’s leave those aside.To really get a Softphone right you need to start with a good audio handling technology. For that you need a good audio system on your computer i.e. good microphone that does not pick up noises from the disk, good speakers and low delay audio drivers and hardware. Add to that a decent CPU power and you can start with the most basic requirement of a Softphone which is Echo cancellation. Without Echo cancellation you will be annoying people calling you or suffer constant feedback.

I don’t accept a headset as viable solution to remove echo, it is just not convenient. Echo cancellation or AEC takes significant CPU power and is a delicate process, the CPU power is usually needed for a Wideband Codec (like the one used by Skype) low CPU power narrow band Codecs, will be sufficient to make a call to a standard telephony systems (the PSTN), but will not have any benefits when working with another Softphone on the other end.

The next step is dealing with internet connectivity, which instantly tests the Softphone jitter buffer management capabilities which determines the latency of the call. I use at my house wifi N router with a 802.11 B Bridge for my VoIP hard phone and I am getting very good results, but wifi environments or hotel LANs are seldom reliable, and intensify the jitter and packet loss problem that need to be dealt with. Jitter Buffer handling technologies exist on any VoIP hard phone, and eventually deal with other problems as well such as packet loss (in case the Codec does not take care of that) . The jitter buffer management technologies on a hard phone handle the network problems, on a PC however they need to deal with many issues created by the OS.

Windows is not a real-time operating system and the last thing you want is for the OS to add artificial jitter to the packets arrival times when the OS decides to access the disk or open outlook. Mishandling of the Jitter affect the call quality to large buffer translates to unacceptable latency too small translate to voice breakups.

All the above indicates that there are patents and royalties and cost associated with each copy of a Softphone. You probably see the same news we all do, where each month another VoIP company is settling yet another patent infringement. Additional cost aspect which is associated with a softphone is that they usually associated with or expected to have unlimited calling plans, Add to that high hacking probability due to the open nature of personal computing and you see another costly front opening for the VoIP companies which is the need to handle fraud.

As you can see all this is not trivial, and hence there are only few good soft phones available – I am still looking for one. I hope that PC manufacturers will create some standard for the audio system that they can call VoIP ready and hence some of those problems will go a way and will make the task of developing a good Softphone much easier in the future.

Personally I often use skype and skype-out with my skype friends and when I travel.
As I joined and got my own VoIP hard phone, I started using that as my main communication tool for my home office, every time I dial, the dialing speed and the sound quality are so significantly better that I simply don’t use the PSTN anymore, In fact I got rid of one land line, and now waiting on ATT to cancel my second.

Since I always travel with my Cellular PDA Phone, I use the Virtual Office service to direct my office calls to my cell phone, in case I don’t pick up at my desk phone. Using the Virtual Office service, I also directed calls to my home numbers (which I transferred to using LNP) to my cell phone.As for Voicemails, I use the Virtual Office service of to collect them all (which ever source they come from e.g. office, home or cell), and I read them all from my e-mail on my PDA Phone. What it means is that the need for a Softphone is really reduced. It is reasonable to assume that VoIP companies realize that and simply decided to invest fewer efforts on the Softphone business.”

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