Patent GB-414301-A (GB)
Title: Improvements in or relating to impulse transmitting arrangements for use in telephone systems
IPC: H04M1/274
Filed: 1934-01-31
Abstract: 414,301. Impulse transmitters. GIORDANO, P., 16, Via Riccardo Wagner, Alessandria, Italy. Jan. 31, 1934, No. 3256. [Class 40 (iv).] In an impulse transmitter of the keyboard type comprising six rows of ten keys, each key can control the transmission of either one digit of a six-digit number in accordance with its position on the keyboard or the whole six digits of an arbitrarily-selected number, the choice between these two functions being effected by operating one or other of two auxiliary keys. Each key 30, Fig. 5, has pivoted to it a terminal block carrying seventeen terminals 28 arranged in two rows as shown in Figs. 3, 10, six of the terminals I-VI of one row being jumpered to the ten 1-0 of the other row in accordance with the six digits of a particular subscriber's number (286004) whilst the remaining terminal his jumpered to that one of the row 1-0 which corresponds to the position of the key on the keyboard (as shown, the ninth in the first row). When a key 30 is depressed the terminal block is moved forward so that the terminals make bridging connections between a series of ten digit wires 1-0 multipled over the whole keyboard and two groups of sequence wires I-VI and h--w. A depressed key is locked by a locking bar 32 engaging a projection 35 and is released by a common release key Z, the arrangement being such that only one key in a rod can be depressed at the same time. When it is desired to call the six-digit number allotted to a single key, auxiliary key N is depressed completing a circuit at contact H for connecting transformer T over leads 50, 51 to commutator magnet U which advances its wipers s, t, to a start position.. Wiper s is connected up over contact N<1> of key N and completes a circuit over lead 53 for relay 39 which operates its mechanically-locking armature 11 to start a motor M driving a plate A which carries on one side a stepped segment L and commutator segments i<1>, i<11>, and on the other side magnets E, F. At each rotation of plate A a pin P operates contacts D to advance commutator wipers s, t, one step, and in each of the positions I-VI of wipers, magnet E operates over segments i<1>, L, one of the brushes K, and a jumpered connection at the operated terminal block, for a varying fraction of a complete revolution of A depending on which of the brushes K is connected up. Magnet E closes a higher-voltage circuit for magnet F which tilts a pivoted arm V causing a projection 25 to engage a number of a series of spaced springs 22 to transmit a corresponding number of impulses over the line. At the same time the movement of the head 20 of the magnet core 19 permits springs 23, 24 to close to shortcircuit the telephone instruments. After the last digit, wiper s completes a circuit over lead 54 for winding 13 which releases the locked armature 11. The operation is similar when auxiliary key C is depressed with the exception that wiper t is connected up and the six digits transmitted are determined by jumperings such as h-9 closed at six keys one in each row of the keyboard. Instead of the springs 22, a projection 40 on arm V may engage the fingerholes of an ordinary dial, the commutators s, t, having in this case neutral positions between each two working positions in order to provide time for the dial to return to normal between digits. The multiple-wires 1-0, I-VI, h-w, are in the form of helices of small diameter which provide resilience.