Abstract: An application module interface (AMI) is disclosed that allows one or more modules to access voice or data channels in a private branch exchange environment. The AMI provides a number of hardware signals to the telephone terminal and/or modules. The hardware control signals include module present, phone receiving OK and module receiving OK. The module present (MP) signal indicates that a module is plugged into the AMI electrical interface. The module receiving OK (MOD-OK) and phone receiving OK (PHONE-OK) signals indicates that the module and phone, respectively, is receiving valid AMI control channel messages. The hardware control signals permit the presence of a telephone terminal and/or a module to be detected, as well as to detect the disruption of an AMI connection. The hardware control signals are used to implement a start-up, recovery and tear-down mechanism.

Abstract: An asynchronous interface for coupling data between a terminal and a data module is provided. The asynchronous interface directly determines and matches to the rate of serial data being transmitted by the terminal and received by the data module with minimal involvement of a processor associated with the data module. The asynchronous interface determines the rate of the data being transmitted by configuring counting circuitry therein for measuring the period of the start bit in the first received character whenever the speed of data being transmitted by the terminal must be determined. The asynchronous interface then adjusts to the newly determined data rate and receives the remaining bits in the first character and subsequent characters at the new rate. The processor is involved only to request that the asynchronous interface determine the incoming data rate and match to it and, once the data rate has been determined and matched, to process the recovered characters and this new rate.

Abstract: A portable frequency modulation transmitter (1) for voice or data is disclosed for operation at infrared frequencies. The transmitter comprises keyboard (200) or microphone (402) input capability and dual modes of use. In the data mode, carrier is generated when the keyboard is operated and is not generated when the keyboard is idle in order to conserve power. In the voice mode, either voice or data may be transmitted, data having priority over voice. A series connection of two variable modulus counters (302, 303) and other counters (304, 305, 306) provide a frequency shift keyed data signal, marker data signal, marker data frames between data frames, parity insertion and other features. In the event that the local battery power level falls below a particular level, a particular word is inserted in the applied binary data input.

Abstract: A portable frequency modulation transmitter (1) for voice or data is disclosed for operation at infrared frequencies. The transmitter comprises keyboard (200) or microphone (402) input capability and dual modes of use. In the data mode, carrier is generated when the keyboard is operated and is not generated when the keyboard is idle in order to conserve power. In the voice mode, either voice or data may be transmitted, data having priority over voice. A series connection of two variable modulus counters (302, 303) and other counters (304, 305, 306) provide a frequency shift keyed data signal, marker data signal, marker data frames between data frames, parity insertion and other features. In the event that the local battery power level falls below a particular level, a particular word is inserted in the applied binary data input.

Abstract: A mobile microphone-transmitter assembly is disclosed which comprises a microphone, a plurality of infrared light emitting devices, electrical apparatus connected between the microphone and the devices to energize the devices in response to inputs to the microphone and a mechanical structure for supporting the devices to produce a substantially omnidirectional, horizontal radiation pattern when the structure is worn by a user and the devices are energized.

Abstract: A hands-free telephone system is disclosed utilizing an infrared transmitter and receiver to permit wireless speech transmission. The transmitter uses frequency modulation imposed on the infrared signal and includes carrier shift signaling arrangements for indicating a low battery condition and transmitter turnoff. The receiver utilizes a noise detection circuit for permitting remote turn-on, for squelching noise in the voice path, and for feeding an alerting signal to a loudspeaker to indicate that the received signal is excessively noisy. The portable transmitter must then be moved or redirected to provide a better line-of-sight signaling path.