Use of VoIP with Low Quality Handsets

Posts: 4 · New Forum Member Joined: May 13, 2005 Posts: 4

Has anyone noticed when you are speaking to someone, who is using a low quality handset ($5-type variety "special"), that the Quality of Service is much poorer than when you are speaking with parties who have a more standard quality of handset?

I can't say I am aware of the same QoS issue when I use the POT type of service but sure do notice it when I am using the Vonage service to speak to the same parties.

Posts: 1424 · Posted: Sun May 15, 2005 11:25 pm Post subject:

A key aspect of Voip is the conversion of voice signals to digital. This is accomplished through the various CODECs available. These CODECs have been developed to recognize the sound of speech and convert it into the smallest amount of digital data possible. This apparently works well for the vast majority of spoken languages with some exceptions (possibly Khoisan languages).

If you have registered on a web site, especially for a contest, you may have been asked to enter a word or string of characters displayed in a distorted image to prove you were human. Poor quality phones do this same type of distortion to the audio on your calls. While it remains possible for you to understand the audio, you may not even notice the distortion, it becomes a very difficult task for the computer to accomplish. When the algorithm starts making bad guesses it can result in gaps or mangled audio.

One other characteristic of these CODECs is their failure to recognize DTMF (touch tone) codes. This forces the hardware to detect those tones ahead of the CODEC and send a separate message to inform the receiving end of the key press.

As computer power increases and advances are made in voice compression CODECs will become better at recognizing and picking out the spoken words. One big advantage of this is that, even now, calls made from noisy places are often more understandable because a lot of the extraneous environmental noise is being ignored by the CODEC.

I have not personally noticed this on my calls. Are you using the highest quality setting or have you adjusted downward to save on bandwidth?

Posts: 4 · New Forum Member Joined: May 13, 2005 Posts: 4

Stephen,

Thanks for your reply. I have my setting on the highest setting (bandwidth). That has improved the quality. Just notice that when I am conversing with one of my contacts, who does have an ultra-cheap phone handset, that the quality is considerably poorer than we I am conversing with other folks. Also notice from the same contact, now that you mention it, that I am picking up a lot of background noise (e.g. a radio playing in the background in his home) drowns out some of the conversation between us.