Abstract: A telephone receiving apparatus (100) rigidly retains a telephone handset (200) without the need for a release lever. In the preferred embodiment, a moveable boss (108) and a rigid boss (106) engage corresponding notches (208 and 206) in the earpiece of the handset during insertion. The handset (200) is removed by moving it forward until the rigid boss (106) is cleared. The improved telephone receiving apparatus of the present invention may be advantageously utilized in mobile telephones and a variety of other applications where a telephone handset is subject to shock and vibration during normal use.

Abstract: A data transmission system is described where data signals are bidirectionally transmitted between a data transmitter and a plurality of data receivers in a self-clocking bit streams carried on true data and complement data signal lines and a non-return-to-zero (NRZ) bit streams on a return data signal line. According to an inventive data transmission scheme, data signals are transmitted by the data transmitter by utilizing the four possible two-bit binary states of the true data and complement data signal lines. Of the four two-bit binary states, a word state is provided before and after the data signal and a one state or zero state followed by a bit state is provided for each bit of the data signal. The data receivers detect the bit state to recover a bit clock signal and detect the one state and zero state to recover an NRZ data signal.

Abstract: A demodulator is described for demodulating phase-encoded data signals transmitted on a noisy communication channel, such as, for example, radio communication channels of a radio communication system. The demodulator includes a digital phase-locked loop for phase-locking to the mid-bit transitions of the phase-encoded data signal, which, in the preferred embodiment is encoded according to the well known Manchester coding format, and further includes demodulating circuitry for sampling the phase-encoded data signal a predetermind number of times, weighting the samples according to predetermined weighting factors, totalizing the weighted samples for each bit interval and comparing the totalized samples to a predetermined threshold value for ascertaining the logical state of each bit of the phase-encoded data signal.