| 摘要 |
<p>To protect the data in a passive optical telecommunications system comprising a common telecommunications facility and a plurality of decentralised telecommunications facilities, a public code is in each case determined from a secret code predetermined in a decentralised telecommunications facility, which public code is transmitted upstream to the common telecommunications facility where it is used for coding secondary code information in order to adapt the decentralised facility to transmission parameters individually provided in the common facility for this decentralised facility and repeatedly changed. The decentralised facilities can calculate new codes from time to time. As transmission parameters, the time-slot allocation in a multiplex frame and also the initial position and/or structure of scramblers can be changed. <IMAGE></p> |
