MULTIPLEX INTERFACE FOR A COMMUNICATION CONTROLLER

Multiplex interface (17,3) to be connected to the line scanning means (1) of a communication controller in order to exchange data and control bits between the line scanning means and the user lines attached to the communication controller. Transmit and receive synchronous multiplex links (3-T,3-R) connect the line scanning means to the line users through multiplexing means (17), the data and control bits being exchanged on the transmit and receive multiplex links in synchronous frames wherein at least two slots are assigned to each user line, the structure of the two slots being identical for all types of user lines and comprising: -a n-bit data slot which include a variable number x of valid bits depending upon the line speed of the user line assigned to the data slot, said number being indicated by a variable delimitation pattern comprising a first delimiting bit set at a first binary value (1) adjacent to the data bits and (n-x-1) bits set at the second binary value (0) adjacent to said first delimiting bit, and -a n-bit control slot wherein a first bit is used as global validation bits in case the data slot comprises n valid bits (x=n), this bit being set at the first binary value (1) when the data slot comprises n valid bits and at the second binary value (0) if it comprises less than n valid bits, and the n-1 following bits being used for exchanging control information.