Abstract: A device for testing the digital waveforms in a special purpose multi-channel transceiver system designed to operate in a tactical environment. As selected waveforms are presented to the test device, they are randomized over a fixed time period creating a unique signature for comparison with a prestored signature at the end of the period. Uniquely assigned light emitting diodes identify which, if any, of the sequentially examined waveforms are incorrect. Provisions are included for latching the light emitting diodes in their illuminated state in order to detect non-recurrent fault conditions.

Abstract: A low voltage two wire to four wire telephone circuit converter apparatus utilizing a series pair of amplifiers to provide a transmit data out signal that is referenced to analog ground. A pair of amplifiers in parallel to receive a receive data in signal which is referenced to analog ground and apply it to the telephone unit. A signal adapter converts the telephone ring signal to a constant one level for transmission over a digital channel in a fiber optic link.

Abstract: An input-output converter permits the integration of terminals and transmit and receive equipments that operate at given logic voltage levels and character formats into communications system that operate at different logic voltage levels and character formats. The input-output converter includes a universal asynchronous receiver transmitter that converts m bit serial data into n bit parallel data in a receive mode and n bit parallel data to m bit serial data in a transmit mode while stripping and adding asynchronous start-stop bits. The input-output converter also includes logic voltage level converters that convert digital data to appropriate logic voltage levels for each function.