Abstract: A TDM PCM communication system includes a plurality of user terminals, a switching network and a CPU for controlling the establishment of transmission paths between the user terminals and the switching network for the transfer of information between predetermined ones of the user terminals. An incoming path carries information bits from the user terminals to the switching network and an outgoing path carries information bits from the switching network to the user terminals. The switching network includes means for transferring single information bits each residing in a time slot period from the incoming path to the outgoing path. The transferring means includes an exchange means for effecting a bilateral exchange of information bits in fixed pairs of time slot periods, whereby paths for information bit transmission are periodically provided between ones of the user terminals, as determined by the CPU.

Abstract: Pretension threading device which includes two thread deflecting means supported on opposite sides of a pretension, and arranged to deflect thread caught and drawn into the thread deflecting means into wrap around the pretension. One thread deflecting means extends to beyond the pretension in a direction away from a thread supply tapering to a point beyond the pretension spaced from the adjacent sewing machine housing. The other thread deflecting means lies in covering relationship to the pretension, terminating at the pretension and tapering beyond the pretension device in a direction away from the thread supply to the adjacent sewing machine housing.