Monday, November 2, 2009

Echo - How to solve echo as feedback

If you hear your own voice echoed back to you when you are talking, you are actually hearing sidetone echo.

Sidetone echo is intentionally introduced on all IP phones as a 'comfort' to the customer. When IP Phone technology was initially engineered, focus groups were created to evaluate the new technology. Most people complained that the phone 'felt' as though no call was active because the slight background buzz (whitenoise) and their own voice was not audible. Users reported that they thought all the phone calls were disconnected or muted.

So the original team of engineers artificially introduced sidetone and whitenoise which made IP phones 'feel' more like a traiditional phone system.

To eliminate sidetone echo:

1. Login to the IP PBX (centos) as root
2. cd /home/PlcmSpIp
3. Create or modify your phone override file:

vi 000000000000-phone.cfg "MAC-ADDR"

Example:

<?xml version="1.0" standalone="yes"?>
<!-- EU Name's PC501 Overrides -->
<phone_config>
            <overrides

                voice.gain.tx.analog.handset="-3"
                voice.gain.rx.analog.handset.sidetone="-16"

          />
</phone_config>

NOTES:

Sidetone is in increments of 2 -12 (loud) to -24 (soft) default is -24.
tx.analog (microphone) is in increments of 3 12 (loud) to -36 (soft) default is 3.

6. Reboot your phone to pick up the new settings.

Hold down until it chirps and then says rebooting.

VOL -
VOL +
HOLD
MESSAGES

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