Patent GB-669384-A (GB)
Title: Improvements in or relating to connecting devices for automatic telephone systems
IPC: H01J17/40
Filed: 1946-11-11
Abstract: 669,384. Automatic exchange systems. TELEFONAKTIEBOLAGET L. M. ERICSSON. Nov. 11, 1946 [Nov. 12, 1945], No. 33513/46. Class 40 (iv). [Also in Group XL (a)] An automatic telephone system connecting device, of the kind comprising a number of gaseous discharge tubes 11<SP>1</SP> &c., each having a common envelope containing in a common gas atmosphere a plurality of electrodes 13<SP>1</SP> &c. of one polarity and a single electrode 121 &c. of opposite polarity common to all of said other electrodes, has the said single electrode 121 &c. of each tube arranged to shield the other electrodes from each other and disposed so as to divide the gas atmosphere into a number of different chambers, each, Fig. 1, or some, Fig. 2, of said chambers containing one of said other electrodes 13<SP>1</SP> &c., a number of incoming .lines 19<SP>1</SP> &c. each connectable over a contact 20<SP>1</SP> &c. and an impedance 21<SP>1</SP> &c. to a single electrode 12<SP>1</SP> &c., and a number of outgoing lines 14, 15, 16, 17 each connected to one of the other electrodes 13<SP>1</SP> &c. in each of said tubes, each outgoing line being connected over impedances 18 to one pole of a current source, the other pole of which is connected to each incoming line 191 &c. The electrodes 12<SP>1</SP> &c. may be cathodes and the electrodes 13<SP>1</SP> &c. anodes or vice versa. The voltage of the current source is such as to produce ignition between the single electrodes 12<SP>1</SP> and one of the other electrodes 13<SP>1</SP> &c. immediately upon closing of a contact 20<SP>1</SP> &c., whereby the corresponding incoming line 19<SP>1</SP> &c. is connected to the outgoing line belonging to the other electrode. The voltage drop in the impedance 18 connected to the outgoing line 14 &c. reduces the potential of this line in such a way that the potential of all electrodes in other tubes connected with the same outgoing line is insufficient for producing ignition between these electrodes and the single electrode on connecting another incoming line to its corresponding tube, while the ignition of such tube takes place between its single electrode and another of its electrodes which is connected with an outgoing line not occupied at the same instant. The Specification as open to inspection under Sect. 91 comprises also a discharge tube 1, Fig. 1 (Cancelled), containing two electrodes 2, 3 in each of four discharge chambers formed by partitions 4, a small plate 5 being provided if only one particular electrode in each group is intended to be used as a cathode and mica plates being inserted on each side of the discharge spaces for shielding, and comprises also a discharge tube 1, Fig. 2 (Cancelled), containing four completely separated discharge paths in each of which one of the electrodes 6, which may be used as a cathode, encloses or shields the other electrode 2, mica plates being placed above and below the electrode 6 or metallic closing of one or both ends of the electrode 6 being used, shields 4 separating the electrodes 6 and, to make it possible to use both electrodes as cathode, the inner one being formed with a greater surface, for instance with a small plate as shown in Fig. 1 (Cancelled), or being formed as a cylinder coaxial with the electrode 6. This subject-matter does hot appear in the Specification as accepted.