Have new install with (4) KX-TCA 385 and (1)KX-T0158. During inbound call customer hears noises and a feedback of their own voice for 20-30 seconds and then conversation is clear for the rest of the call.
Never heard of that. Have you tested it with a desk phone or before the system?
What lines are on the system
The KX-DT543 sounds great. Just the PS
I have not come across this problem on digital system before either
Have you tried a new cell station?
you could try an echo cancel card and enable extension to analogue.
I'll be back on site tomorrow and give that a try.