... T200 Polaris headsets require no amplifier! They plug directly into your headset-ready telephone! What' ... feet cord that has a modular plug on the other end.You plug this modular plug into the headset jack ... SoundPoint IP Phone Series, Models 300, 500 (rev. 5 or later), 550, 600, 650 POLYCOM IP300, IP301, ... DP5000-Series Ulytel: Ulytel 1, Ulytel 2, Ulytel 5, Ulytel 4 (2-line) Uniden: 420 and 450Binaural ...