Multi-mode digital enciphering system

摘要

The specification discloses an electronic digital enciphering system which is selectively operable in a plurality of different modes. The system may be operated in an off-line mode for preparing enciphered message tapes prior to transmission via teleprinter message circuits. The system may also be operated in an on-line asynchronous mode wherein a sending station may asynchronously transmit enciphered data on-line to a remote receiving unit, synchronization being provided by the start/stop pulses of the individual digital characters. The system may also be operated in an on-line synchronous mode wherein a sending and a receiving unit are automatically synchronized in time by local self-contained clocks in order to bridge fades or interference in a transmission medium such as radio telegraph, or the like. The system may be utilized on either half-duplex or full-duplex communication channels.