FIELD: communications engineering; answerback paging systems for message transmission. SUBSTANCE: system primary station transmits sequence of messages addressed to respective secondary station over direct line. Signal inviting secondary stations to transmit their responses, for instance in the form of code-division multiple-access signals, is transmitted by primary station. During reception primary station analyzes only illegible responses, compares them with primarily transmitted messages, and transmits acknowledgement of reception to respective secondary stations. Then primary station generates one more invitation for stations whose responses were not detected to send their response over backward communication line. Responses found illegible are processed as before and their reception acknowledgements are transmitted together with other invitation over direct communication line. Cycle of these operations is repeated as many times as predetermined or until decision is taken that all illegible responses have been received. Proposed method may be used for processing service requests and responses to messages transmitted over direct communication line. EFFECT: enhanced flexibility of answerback message transmission systems. 20 cl, 9 dwg
