Screech - Immediately after the first ring, the system sends the caller ID information to your phone. On a DTerm digital phone you don't hear it, but on a regular analog phone you can hear this digital signal. It sounds like a modem or fax hiss, and if you pick up at the same time it's coming down the line you can hear it (the person calling you can't). We can turn it off if you request, but then you won't receive caller ID.
Stutter - On an analog phone, if your dialtone "stutters" whan you pick up, it means you have a Voicemail Message Waiting. Didn't know you had Voicemail? Check the Knowledge Base articles on that.