Patent GB-342370-A (GB)
Title: Improvements in or relating to printing telegraphy
IPC: H04L5/22
Filed: 1929-11-05
Abstract: 342,370. Type-printing telegraphy. STANDARD TELEPHONES & CABLES, Ltd., GRACE, B. B., SKILLMAN, T. S., ROCHE, A. H., and SANDEMAN, E. K., Columbia House, Aldwych, London. Nov. 5, 1929, No. 33636. [Class 40 (iii).] In a type-printing telegraph system using the five-unit code with the elements represented by five different frequencies, the signals comprise combinations of these frequencies taken one or more at a time and sent simultaneously, and themselves control the conditioning of the receiving apparatus to receive successive signals. The transmitting apparatus consists of five automatic transmitters 1 .. 5, each having contacts a .. e operated by a tape to energize simultaneously through the selected contacts of a distributer bank DR and a step-by-step switch a combination of the relays A .. E, connecting to the line L through filter circuits FR the selected frequencies derived from oscillating circuits or rotating commutators on a common motor shaft. The switch at each step engages a sixth or upper contact through which is energized a stepping magnet B of a preceding transmitter to move forward the tape in readiness for the next signal from that transmitter. The received signal selectively operates one or more tuned relays A<1> .. E<1> energizing corresponding relays F .. K through condensers. The operation of one or more of the relays F .. K energizes a relay L. At the same time the relays A<1> .. E<1> energize a relay SL, and prepare printermagnet circuits through the appropriate contacts of each of three distributers SA, SB, SC. A relay P energized by the relay L operates a relay S closing a circuit through a distributer arm SD and a contact connected to a set of printer magnets special to one of the distributers SA, SB, SC and at the same time energizes a slow release relay SAB of the stepping magnet SAM of the distributer SA. A circuit T is also closed which then completes the circuit of the stepping magnet SDM of the arm SD. If two successive signals are the same, none of the relays F .. K will be energized and relay L will not be operated. The release of relay L releases a relay R to operate a timing circuit TC and after a definite time, corresponding to the discharge of a condenser, a relay Q energizes a relay O, which operates the relay R. Relay P is energized through its left-hand winding, and with the operation of relay S, the sequence of operations is repeated. If relay L has not been operated again, relay O releases relay R to restart the operation of the timing circuit TC. If relay L has been reoperated, a relay M is de-energized and a relay N opens the circuit between the relays O, R. On the cessation of signalling, the relays O, R continue to measure off time intervals and the relays P, S are operated, but the de-energization of the relay SL opens the circuit of the stepping magnet SDM of the distributer SD. The brushes in moving over the contact banks SA, SB, SC engage a sixth contact energizing the resetting magnet RM of a preceding printer. In an alternative arrangement (Fig. 3, not shown), a pause of no current is left between the transmission of successive signals and at the receiver direct current relays operated by tuned relays complete the circuit of the appropriate printer magnets and of a relay energizing the magnet of a step-by-step distributer switch, engaging a sixth contact energizing the resetting magnet of a preceding printer. If the system is employed in telegraphy and telephony frequencies below the voice frequency range are employed. A primary distributer such as SD, Fig. 2, may be incorporated at the transmitting end.