We are currently testing a few SPA942 and SPA964. We have found that when someone is on speaker phone the other person can sometimes hear themselves speaking. Also there tends to be a lot of background noise and an overall 'in the can' sound(sounds echo and it sounds like you are working in a can).
I'm looking into adjusting the speakerphone input gain to address this problem. Is this the place to start? Are there other setting that can/may need to be adjusted?
Also I was wondering if the PBX has any influence of this type of thing?
There can be MANY causes of echo. They range from QoS to broken hardware. The best place to start would be to adjust the volume of the speaker phone to the lowest tolerable by the user. If they must have it as loud as possible, try adjusting the phones distance from other electronic devices ( I found if you put 2 phones on speaker and place them 6 inches apart there is an awful sound). You might look into adjusting the jitter buffer/implementing QoS on your network (see the Admin guide for the proper setup of the phones). You could also look into other codecs. If you are on G711 look into maybe G729 or G726 (G729 first).
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