Patent GB-1193207-A (GB)
Title: Card Telephone Dialling Machine.
IPC: H04M1/278
Filed: 1968-02-26
Abstract: 1,193,207. Impulse transmitters. SONTRANIC Ltd., and R. G. LANE. 26 Nov., 1968 [26 Feb., 1968], No. 9266/68. Heading H4K. [Also in Division G4] In a punched card controlled automatic dialler the card drops under gravity and is arrested intermittently by an electromagnetically operated plunger. The arrangement shown employs a plastics card 12 which has a first column of holes 22, individually engaged by the end of a plunger 20 reciprocated by pulsing an electromagnet 16 to stop the card downwardly under gravity, and five other columns C1 to C5 of hole positions in which the holes are part punched and can be pressed out as required. The columns C 1  to C 4  store the wanted number (one digit per row of four holes) and the fifth column C5 is holed at appropriate row or rows if one or more long pauses between the transmission of groups of dialled digits is required. The holes in columns C1 to C5 are sensed by a row of photoresistors 26 and a photoresistor (27, not shown) positioned to receive light via light guides and the holes from a common source. A further photoresistor 30 senses for the presence of the card. The columns of holes are positioned such that if the card is inserted the wrong way round no holes are sensed. When the card is inserted in the dialler it drops until its lower edge abuts the plunger 20. The photoresistor 30 detects the presence of the card and causes the electromagnet to operate momentarily so that the card drops to a position in which the plunger engages the lowest hole of the column 22 and the lowest hole position of each of the columns C 1  to C 4  is adjacent photoresistors 26. The photoresistors 26 are pulsed with enabling voltage and those which receive light by sensing a hole in their columns move to their low resistance condition and pass the pulses to corresponding stages of an electronic counter. Each row of holes represents the complement of a decimal dialling digit and thus the counter is initially set to this complement. After a short interval a clamp signal on a pulse generator is removed causing pulses to be entered into the counter and transmitted to line via a relay. When the count of 16 is reached this state is recognized by an "OR" gate connected to each bi-stable of the counter. The generator is again inhibited and the electromagnet is 16 again pulsed to drop the card to a position in which the next line can be read. Each row is read in like manner until a row with no holes is sensed. When this occurs an AND gate is enabled by co-incidence of the output of the OR gate with the enabling voltage pulse to the photoresistors 26. The output of this AND gate sets a bi-stable causing the electromagnet to operate continuously until the card drops out of the bottom of the shoot at which moment the bi-stable is reset. A push button is provided and arranged when pressed to set this bi-stable and terminate any dialling operation which is in progress. If during a dialling sequence a hole is detected in column C5 the period during which the pulse generator is inhibited is lengthened to provide a longer pause between groups of dialled digits. Alternatively the cells 26 could control the gating of various tone combinations possibly via a code conversion matrix if tone dialling is preferred.