Telecommunication switching network having a multistage reversed trunking arrangement

A telecommunication switching network having a multistage, reversed trunking arrangement and switching on a four wire basis, said switching network being constructed to operate as a pulse code modulation (PCM) time division multiplex (TDM) network, comprising:

• a number e . v . g . of single channel subscriber lines connected to a first switching stage of said network wherein said subscriber lines are divided into a number g groups, each group containing a number v subgroups and each subgroup containing a number e terminals,
• a number e of termination coupling circuit means in each said subgroup in said first switching stage for supplying information on said subscriber lines in PCM/TDM form, each said termination coupling circuit means having an input individually conncted to a said subscriber line,
• a number of g.v of TDM trunks, said trunks being individually connected to outputs of the said termination coupling circuit means in differing ones of said subgroups, each said trunk being constructed to carry a number z of time slots thereby forming a number z.v.g connection channels from said first to a second switching stage,
• a first number g of TDM switching matrices in a second stage, each switching matrix having v inputs and g outputs, each said switching matrix having inputs connected to those of said TDM trunks connected to the said termination circuit means in a given group and
• a second number g of TDM switching matrices in a third stage having g inputs, each of which is individually connected to an output from a said first TDM switching matrix, said third stage having outputs for connection to other switching networks.