Time-assignment speech interpolation

At the time assigned speech interpolation (ZSI, English time -assignment speech interpolation, TASI ) is a system developed by Bell Labs dynamic frequency division multiplexing in which a subscriber is only one channel is assigned when he actually speaks.

Here, the channel allocation is performed only in the active phases of the communication relationship. In the quiescent phases, the shutdown of the respective channel is to be used by another party. If resumed speaking, a new channel allocation is done on a straight free channel. This method requires a high management overhead, and an additional transport of the current channel occupancy information.

First practical application

The second trans-Atlantic cable TAT -2 was put into operation on 22 September 1959. The number of voice channels could be increased in the spring of 1960 by the TASI process from initially 47 to 87.