Patent GB-247648-A (GB)
Abstract: 247,648. Automatic Electric Co., and Wicks, J. Nov. 17, 1924. Automatic exchange systems; impulse transmitters.-A subscriber in addition to the usual manually-operated calling device, is provided with an automatic impulse sender controlled by a set of keys so that the operation of a single key results in the transmission of all the digits of a wanted number; the keys are allocated to numbers which are frequently being called. In the arrangement shown, the operation of a key K<1> - - K<5>, Fig. 1, energizes a relay R' - - R<5>, which prepares stopping circuits extending over bus-bars B<1> - - B<9>, Fig. 2, to the contacts of a sending switch S. The stopping circuits are made operative in turn to control the sending switch S by means of a sequence switch S'. Assume that the subscriber A, Fig. 1, removes his receiver and operates the key K<1> to call automatically subscriber 63006. On removing his receiver, the polarized relay 124, Fig. 2, is energized over the talking wires 11, 12 in series with the line relay of the line switch, and closes contacts 126 over which the relay R', Fig. 1, is energized when the key K<1> is operated. Relay R<1> locks up over grounded conductor 35, shunts a resistance 128, Fig. 2, across the receiver and manually-operated calling dial, and grounds conductor 36, thereby energizing a relay 130, which energizes relays 131, 135. Relay 135 closes the circuit of relay 136, which opens the circuit of relay 135, which in turn de-energizes 136. The relays 135, 136 thus operate alternately, each time the relay 136 energizes an impulse being delivered over the calling line at contacts 125, and the stepping magnet 144 of the switch S being energized over armature 138. As the first digit is 6, the front contact of the top armature 16 of the relay R<1> is jumpered over a distribution board P to the sixth bus-bar B<6>. so that when the wiper 122 of the switch S reaches the sixth contact and six impulses have been sent, a circuit is completed over lead 34, and the sequence switch S' in its first position, for a stopping relay 139, which locks up, opens the circuit of the impulse relay 136. energizes the release magnet 143 of the switch S, closes a stepping circuit for the magnet 145 to advance the sequence writch S<1> into its second position, and causes the relapse in turn of the slow release relays 130, 131. Relay 131 opens the locking circuit of relay 139, which re-energizes relay 130 and re-starts the cycle of operations. The timeinterval introduced by the relapse of the slow relays 130, 131. 139 is sufficient to allow a selector to hunt. The remaining digits are sent in the succeeding positions of the switch S<1>. the stopping circuits for the sending switch S extending over armatures 17 - - of the relay R' except for the digits 0, in which case the corresponding contacts engaged by the armatures 18, 19 are not cross-connected at the frame P as the tenth contact of the switch S is permanently grounded. In the sixth position of the sequence switch S', relay 147 is energized over the grounded conductor 36, locks up, and closes circuits for the release magnets 143. 149 of the switches S, S<1>. Ground is also removed from the conductor 35, causing the relapse of relay R', which removes the bridge 128 from the calling line. The subsequent relapse of relays 139, 147 restores all the sending apparatus to normal. When the called party answers, the reversal of current over the calling line by the response of the back-bridge relay, causes the polarized relay 124 to close contacts 150 and light an indicating lamp L at the calling station. If the calling party depresses a key in error, the impulse sender may be stopped and restored by operating a release key R, Fig. 1, which grounds a conductor 47 and energizes the release relay 147. Before making a new call, the calling party must hang up to release the partiallv set up connection. Should a particular key, such as K<2>, be associated with a wanted substation, the call number of which consists of a less number of digits, say three, than the capacity of the sender, the contact engaged by the fourth armature 52 of the relay R<2> is cross-connected at the frame P with the conductor 47 so that when three digits have been sent and the sequence switch S<1> arrives at its fourth position, a circuit is completed for the release relay 147 over grounded lead 36, wiper 121, conductor 31, armature 52, and conductor 47.