With PhoneTray most phones will still ring once on blocked calls. Caller ID information is sent only after the first ring, so PhoneTray cannot block the call before the first ring because it doesn't know who is calling. And it's not possible to suppress the first ring using a modem.
You can disable your phone ringer and PhoneTray will ring through computer speakers instead. PhoneTray doesn't ring through computer speakers on blocked calls or during quiet time. You can also get a phone that has an option to suppress the first ring, like most Philips wireless phones, newer Panasonic wireless phones, RCA Dect 6.0 phones (2101 series or newer) or Uniden Dect 6.0 phones. If you are not sure whether your phone has "first ring suppression" feature, please contact us and tell us your phone make and model. We will check and send you instructions on enabling this feature for your phone if available.
Even without the first ring suppression PhoneTray is effective because it plays a "number disconnected" message to the unwanted callers and they will stop calling after a while. If you get a stubborn telemarketer who ignores "number disconnected", you can setup a custom zap message for that number. DTMF.wav and FastBusy.wav work better than Disconnected.wav for some telemarketers. Please refer to the How to select a message that blocked callers will hear article for more information.