I own BT3520, three pack version and have the same issue on each handset.
No matter if we call out or someone calls in, we cannot hear the person at the other end of the call? They can always hear us but we hear nothing, maybe a slight hiss/buzz at best?
I've currently pulled power from every unit to rest the system in the hope it clears the problem, but would appreciate any other thoughts on the problem.
No reported line issue, this has been ongoing for a couple of days now.
Welcome to this user forum.
Can you try a basic wired phone plugged into your master phone socket to see if that works, as it could be a line fault?
Do you have broadband on the line, if so, can you turn the power off on the router, and see if the phones work properly with it turned off.
I've tried a brand new wired phone with the same issue.
There are no report issues in the area, would this indicate a specific fault with my connection/line?
Possibly a fault on the exchange line card.
Are you a BT Retail customer, do you pay BT for your line rental?
I spoke to BT earlier and they couldn't find a fault testing the line.
I've booked an Engineer for Friday and will have to pay the call-out fee (£129) if the fault is found within my property.
If you have tried the phone in the test socket and its still quiet, then the fault is either on the line, or in the exchange.