Newer customer with SL2100. All phones are digital and trunks are provided by Mediacom via coax and modem.

They complain that while using the speaker on an outside call, there is noticeable echo and feedback. This has happened on more than one phone. Not sure if it was different lines or not.

Would the line calibration affect this? They're getting a couple more lines added tomorrow, so I'll do the calibration on all of them.

Thank you.
Jim