| 摘要 |
<p>The invention relates to a digital switch intended for use in a node in a circuit switched telecommunication network with a distributed switching function. The switch includes a switch memory (8), and a time slot counter (10), which is connectable to the switch memory and arranged to point out an address in the switch memory for cyclical writing of incoming data into the switch on this address. A control memory (6) is arranged for controlling the sequence order for read out of data from the switch memory. The switch memory is connectable via an adapting device (32) to a transmission medium, which is common to a number of nodes in the network. The time slot counter (10) is connected via the adapting device (32) to receive frame synchronisation from the common transmission medium. The control memory (6) is arranged for selecting time slots from the common transmission medium and generating read address to the switch memory (8). According to a first aspect of the invention, the control memory (6) and the switch memory (8) are realized with fewer memory cells than admitted by the address space. According to a second aspect of the invention, each memory cell of the switch memory (8) includes an encryption register (56) and devices to enable encryption of traffic between two nodes of the network.</p> |
