| 摘要 |
PURPOSE:To minimize the number of privacy equipments and to prevent the leakage of privacy by constituting a bundle line with n-split of plural transmission lines and providing a privacy equipment and a line setting equipment branching and relaying the line between terminal stations with n-split at each bundle line. CONSTITUTION:Privacy equipments 7, 8, 9 are inserted to a digital primary group (1.544 Mbit/sec) line. Moreover, interface blocks 11, 12 are inserted to a 1.5mega (1.5M) line. A pulse coding (PCM) system is used for a cryptograph coding system. A digital network is branched and relayed in the unit of 6- channel (384 Kbit/sec) by a synchronizing terminal equipment (not shown). Each of the 4 units forms a privacy signal while being encriptied by a cryptographic part 15-1, and the privacy signal is decoded by a decoding section 15-2 conversely to apply the privacy communication between units.
|
