Abstract: In an apparatus for producing duplicate tapes by transmitting signals reproduced by a master VTR to a plurality of duplicating VTRs for simultaneous recording on respective tapes in the latter; control signals from a bidirectional remote control unit are modulated with a first modulating frequency and are transmitted over a bidirectional control signal line to the duplicating VTRs. If a response is required from one of the duplicating VTRs, response signals from such duplicating VTR are modulated with a second modulating frequency different from the first modulating frequency and, during a pause in signal transmission from the remote control unit, the modulated response signals are transmitted to the remote control unit over the bidirectional control signal line.