Patent GB-191403359-A (GB)
Title: Improvements in Machine Telephone Switching Systems.
Filed: 1914-02-09
Granted: 1915-01-28
Abstract: 3359. Western Electric Co., [Woodward, F. T., acting for Western Electric Co.]. Feb. 9. Automatic exchange systems.-The members of a register-controller equipment are successively associated with the incoming and outgoing circuits by two sequence switches which mutually control each other's movements, the arrangement being that, when the setting of a register has been completed, the register is connected to the outgoing circuit as soon as the way has been cleared for it by the completion of the controlling operation of the register for the previous digit. The sequence switch controlling the incoming circuits is only restored to normal when operations in the outgoing circuits have been completed under the control of the outgoing sequence switch. Registering-operations. When the incoming circuit is connected to the registering-equipment bv the closure of the contacts 11 bottom and 12 top, a stepping-relay 151 is energized and moves the sequence switch 100 to its fifth position. As the switch 100 leaves its normal position, a relay 154 is energized, which connects both windings of a relay 252 to the front contact of the relay 151. The relay 252 is differentially wound and does not respond, but the current in its right-hand circuit, which includes the winding of the hundreds register 25, serves to start the register moving from its normal or zero position. As soon as the register begins moving, it opens, at the contact 27, the circuit by which it was started, but the continuance of its movement until it reaches its next position is ensured by the contact 26, which is closed between each position and the next. The opening of the starting-circuit at the contact 27 has the effect, however, of energizing the differential relay 152, the right-hand winding of which is deprived of its current. The armature of this relay opens the starting- circuit at a second point, so that when the register arrives at its next position, it comes to a stop, in spite of the reclosure of the contact 27. The incoming circuit is then interrupted a number of times corresponding to the complement of the wanted hundreds digit, the last of these interruptions being sufficiently prolonged to give time for the energization of a slowacting relay 153. In response to the first interruption, the relay 151 unlocks the relay 152, so that when the relay 151 is energized again, at the termination of the impulse, the register starting-circuit is again closed, and the register moves into the next position. As the register starts moving, it opens its own starting-circuit and thereby energizes the differential relay 152, as already described, so that when it arrives at its next position, it comes to a stop. The next interruption again unlocks the relay 152, and at its termination the register starting-circuit is again closed, and the same occurs at each succeeding interruption. The last interruption, however, is sufficiently prolonged to energize the relay 153, which de-energizes the relay 154 and moves the sequence switch 100 to its eighth position, so that this interruption is without effect on the hundreds register and merely serves to shift the registering circuits into connexion with the tens register 35. This register is then operated by a set of interruptions corresponding to the complement of the tens digit, and the final prolonged interruption moves the sequence switch 100 to its eleventh position. In this position, the units register 45 is operated, and the sequence switch 100 is then moved to its fourteenth position. Controlling - operations. As soon as the hundreds register has been set and the sequence switch 100 driven forward from its fifth position, the contact 103 is closed and drives the sequence switch 200 to its sixth position, in which the hundreds register is adapted to be controlled by the stepping-relay 251. The relay 251. is connected by the contact 206 across the outgoing end of the controlling-circuit 13, 14 and is energized in series with the line relay of a group selector, which causes the selector to be set in motion. During the selecting movement, the selector intermittently short-circuits the stepping-relay 251, and each of these reverting impulses moves the register 25 forward from one position to the next until it regains its normal or zero position. The manner in which this is effected is similar to that which has been described for the setting of the registers by the impulses in the incoming circuit, the relays 251. 252 acting like the relays 151, 152. Each de-energization of the stepping- relay 251 at the beginning of an impulse closes the starting-circuit of the register. As soon as the register begins moving, it opens the starting-circuit at the contact 27 and thereby energizes the differential relay 252. When the relay 251 becomes energized again at the termination of the impulse, it unlocks the relay 252, and when it de-euergizes in response to the next impulse, is again closes the starting-circuit and sends the register another step forward. Assuming that it is desired to select the eighth group of lines in the selector, which correspond to the digit 7 (the first group of lines being those which correspond with the digit 0), then the register 25 will have been set to its third position (3 being the complement of the digit 7) and will regain its normal position upon receipt of the seventh reverting impulse. Upon reaching its normal position, the register 25 disconnects itself at the contact 28 from the left-hand circuit of the relay 2.52, and connects this circuit through the contact 29 to a relay 253 and to the sequence switch 200. The eighth impulse, therefore, which is sent while the selector is moving to the position for selecting the desired eighth group of lines, does not affect the register 25, but directly energizes the relay 253 and sequence switch 200. The relay 253 opens the controlling-circuit 13, 14 and thereby brings the selective movement to a stop, while at the same time the sequence switch 200 moves forward out of its sixth position. If the setting of the tens register is not yet completed, the switch 200 comes to rest and waits in its seventh position, but if the tens register has already been set and the switch 100 has left its eighth position, the switch 200 is moved at once through its seventh position by the contact 104 and comes to rest in its eighth position, in which the tens register is adapted to be controlled by the stepping-relay 251. In the same way, when the tens controlling operation is completed, the switch 200 is moved to its ninth position, in which it waits until the units-registering operation is completed, whereupon it is moved forward to its tenth position by the contact 105, which is closed when the switch 100 leaves its eleventh or units-registering position. In the tenth position of the switch 200, the units controlling-operation is effected, and the final reverting impulse of the units series causes the switch 200 to move forward to normal. Return to normal. When the switch 200 arrives at its normal position, the contact 208 is closed and drives the switch 100 also to normal, and the whole registering and controlling equipment is then in normal condition. If the call should be abandoned at any stage before the operation of the register-controller is completed, the relays 151, 251 are de-energized, and the apparatus is restored as follows: The relay 153 is energized and drives the switch 100 to its fifteenth position, in which the contact 108 is closed. This contact is in parallel with the contact controlled by the relay 252, and the effect of closing it is to restore the hundreds, tens, and units registers successively to normal. For instance, if the hundreds-controlling operation is proceeding when the call is abandoned, the switch 200 being in its sixth position, the hundreds register is energized in a circuit including the contacts 27, 25, 215 top, 108, the relay 252, and the back contact of the relay 251. When the register reaches its normal position, the circuit is opened at the contact 28, and a branch circuit is closed through the contacts 29, 207 top to move the switch 200 out of its sixth position. Since the contact 104 is already closed, the switch 200 moves at once through its seventh to its eighth position, in which the contact 215 bottom is closed to restore the tens register, The switch 200 is then moved to its tenth position to restore the units register by closing a circuit through the contact 216, and then the switch 200 is moved from its tenth position to normal. Finally, the closure of the contact 208 drives the switch 100 from its fifteenth position to normal.