Remote 2-way transmission audience polling and response system

摘要

A remote response system includes a central control unit and a plurality of remotely-located response units each having keypads for entering a selection from a user. The central control unit sequentially transmits distinct address words and includes redundant receivers for receiving data words transmitted by response units. Each response unit becomes powered-up upon the entry of a user response and transmits a data word, corresponding to the user selection, upon receipt of its unique address word. The central control unit examines the validity of each data bit received and the validity of an entire data word to determine if both a character and its complement are received. If a valid data word is received, the central control unit transmits an acknowledge bit, which powers-down the response unit that sent the valid word. Each response unit transmits its data word simultaneously with the central control unit transmitting the address word for the next unit that is to respond with the transmissions occurring over distinct frequency channels. A clock signal for controlling data word serial bit transmission is derived at each response unit from the address word signal.