Abstract: A torch (10) has a magnet (56) in a passageway (54; 68). Movement of the torch (10) in a flicking motion sends the magnet (56) along the passageway (54; 68) to a position adjacent a reed switch (48). Actuation of the reed switch (48) by the magnet (56) turns on the torch (10).

Abstract: The 16 kbit/s HDLC formatted signalling channel for each of 256 ISDN subscribers is separated from the data channel(s) at the exchange line circuit and TMD multiplexed into a 4 Mbit/s stream provided to a common signalling handler. In the handler, a receiving element processes each new bit of the 4 Mbit/s stream with 47 bits read out of a channel parameter store by a channel number provided by a channel allocation store. The 47 bits include the previous 7 received bits and a message byte address for that channel. When those 7 bits and the new bit form a new deformatted message byte, that byte is written into an incoming message store at a location determined by the current channel number and message byte address. Using a FIFO buffer, messages are read from the incoming message store by a processor in the order in which they are completed.

Abstract: A telecommunications exchange includes line identification apparatus in which signals on additional wires (the `p` wires) (1) which are switched in parallel with the speech pairs are used to identify an originating exchange line circuit. On detection of seizure of the `p` wire (1) at one of a number of call logging points (11) a data signal is transmitted by a transmitter circuit (9). On detection of such a signal a receive circuit (2) adds a plurality of data bits to the signal identifying one of a number of associated `p` wires (1) on which the signal was received and transmits the modified data signal to a receiver multiplexer (4, 4'). On receipt of the modified data signal the receiver multiplexer (4, 4') adds a respective plurality of data bits to the signal identifying one of a plurality of receivers (2) connected thereto and retransmits the signal to a further multiplexer (5, 5').

Abstract: A unitary dynamoelectric machine brush holder formed to provide a brush accommodating recess bounded on three sides by two opposing substantially parallel side segments and a transverse segment. Extending from one of the side segments is a pair of spaced spring retainer members formed to provide respective spring retaining recesses in which is mounted a unitary torsion spring having two coils separated by a loop portion that extends between the spring retainer members into the brush accommodating recess and is arranged to exert pressure on a brush located within the brush accommodating recess.