I've been experiencing a small problem on inbound calls on my PSTN line for a couple of weeks, but I've only recently been able to test it thoroughly. On many inbound PSTN calls, but not all, for the first couple of seconds after I answer an incoming call, there is an annoying echo on the line (primarily my voice echoing). This disappears after a second or two, and then the call is normal, without echo for the remainder of the call. I've also noticed that when I access the PSTN line directly by using the # key, then dial a phone number, I sometimes have this same echo for the first digit or two, then remaining digits are dialed without the echo.
This occurs on all of my telephones, both wired and cordless. I believe this happens on roughly half of the incoming calls.
Any ideas of what is causing this and how to correct it? Thanks!