small electronic device in a plastic (or metal) box with a RJ-11 female connection on one side and a RJ-11 male connection on the opposite side that plugs in between a telephone and the phone outlet on a wall; the device automatically generates DTMF (dual tone multi-frequency) tones of 10-10 prefixes, or any other desired prefix such as the access numbers and passwords of calling cards that enable alternate long distance telephone service; for outgoing calls, the user waits a predefined time period after placing a telephone in the off-hook mode to activate the device
Electrical and Scientific Apparatus