If you are experiencing a problem with call quality on one handset please can you perform the following actions:
1. Replace the receiver (hand piece) with a working one.
2. Replace the receiver (hand piece) cable with a working one.
3. Replace the network cable connect to the handset.
Should the issue still persist with the handset please can you supply the following:
1. Supply the IP address of the handset.
2. Supply the make and model of the handset.
3. Supply the extension number of the handset.