FIELD: communications. SUBSTANCE: both bidirectional pager and control unit of back communication line use database which stores information about set of called receivers and replies of different content. Special format of data of back communication line is used for data transmission between central node and bidirectional pager. Said bidirectional pager has first oscillator which converts non-registered free information about receiver into checked data according to format of data of back communication line, and second oscillator, which generates radio communication data with flag of free information about receiver and message type, data which are related to free information about receiver and are generated by first oscillator, and index of message content according to format of data of back communication line. Called user has freedom to select and respond to calling user without restrictions for calling parties which receive responses. EFFECT: increased functional capabilities. 4 cl, 5 dwg
