Pulse code modulation time division switching system

Claim 2

In a system for switching serially transmitted, time multiplexed, pulse code modulated signals having means for converting signals on incoming transmission lines from serial to parallel form to facilitate switching operations and means for converting said parallel form signals to serial form prior to transmission on outgoing transmission lines, the improvement comprising: addressable storage means having fewer storage locations for said pulse code modulated signals than is required for words which can be transmitted during a time frame of a given channel and accessible by all of said transmission lines for providing a buffer between incoming and outgoing signals and including compensating means for compensating incoming signals when phase differences between incoming signals exceeding the duration of the time channel allocated to each connection.

Claim 3

The improved switching system defined in claim 1 wherein said compensating means comprises: means for receiving incoming signals in the time channel assigned to the corresponding connection and for retransmitting said signals in the first available time channel location appearing thereafter, means for receiving signals in the opposite direction in a time channel location assigned to the connection in question on the transmission line concerned, said time channel location being advanced by one time interval relative to the aforementioned time channel location assigned to the outgoing transmission line, said time interval being equal to the sum of the outgoing propogation time and the return time on the segment of outgoing transmission line leading to a subsequent switching system and defined by a point subdividing said segment of line into halves, said means retransmitting said signals to the time channel location assigned to the connection on the outgoing transmission line, said time channel location being advanced by one time interval relative to the connection on said incoming transmission line, said time interval being equal to the sum of the propogation time and return time on a length of transmission line half the distance to a subsequent switching system.

Claim 4

The improVed switching system defined in claim 1 having at least two common addressable storages sharing the required storage capacity for said switching system, said improved system further comprising at least a pair of auxiliary transmission lines over which each of said transmission lines can be connected to either of said addressable storages.

Claim 5

The improved switching system defined in claim 1 having a plurality of common addressable storages and wherein said incoming and outgoing transmission lines, along with associated converters, are combined into groups with each group having access to each of said addressable storages and further comprising: switching matrix means for connecting said groups to a desired one of said common storages.

Claim 6

The improved switching system defined in claim 4 further comprising: a plurality of auxiliary transmission lines, each of said groups being connected with two of said auxiliary lines and connecting line means connecting each of said auxiliary lines to ones of said common storages through said switching matrix means.