Patent GB-100535-A (GB)
Title: Improvements in Call Distributing Telephone Systems.
IPC: H04M3/62
Filed: 1916-05-22
Abstract: 100,535. Western Electric Co., (Assignees of Williams, S. B.). May 22, 1915, [Convention date]. Exchange systems. - Call-distributing systems are provided with means for automatically indicating to the operator the necessary characteristics of the calling line, for example whether the line is a party line, a private-branch-exchange line, or an ordinary line, and whether it is a measured-service line, a flat-rate line, or a coin-collector line. For this purpose, each line has associated with it identifying-means, and the operator's position is provided with an indicating-device which is temporarily associated with a calling line when this is extended to an operator and is controlled bv the identifying-means associated with the line. The form of indicating-device described consists of two groups of lamps controlled by groups of impulsecounting relays, one group indicating the character of the calling line and the other the class of service to which the line is entitled. The indicating- device has control over the circuits by which the operator meters the call or collects the coin, so that the circuits which the operator controls are automatically adapted to the class of service for which the line is intended. The depression of the operator's charge key thus meters the call or collects the coin as may be required. Fig. 1 shows three calling lines of which A is assumed to be a P.B.X. message-rate line, B a party-line coin-collector line, and C an individual flat-rate line. Each line is provided with a fourth terminal connected with the identifying-means 13 which is arranged to produce in each of nine paths 1 - - - 9 combinations of current impulses, divided into two groups, which operate the two groups of lamps forming the indicating device. The fourth terminals of the lines are connected to the paths 1 - - - 9 according to the class of line and the nature of the service to which it is entitled. Each group of impulses consists of one, two, or three impulses as represented by the crosses which denote an interruption in the circuit, and each group is preceded by a starting or pick-up impulse from the interrupters 110, 109, which bring the indicating-device into a condition to respond to the group of impulses immediately after from the identifying-means 13. The interrupters 109, 110 form part of the device 13, but are shown separate to facilitate the description. A constructional form of the device is described. The indicating- device consists of two groups of three lamps 82, 83, 84 and 92, 93, 94 controlled by pairs of relays 76, 77.. 90, 91. The first group of lamps and relays is controlled by the impulses following the pick-up impulse from the interrupter 110, and serves to indicate the class of line, while the second group of lamps and relays is controlled by the second group of impulses and indicates the class of service to which it is entitled. Connexion of calling line to indicating-device. A calling line is connected in known manner by the switches 11, 12 to the connecting-circuit 64, 65, 66, and the relay 113 moves the sequence switch 165 into its seventh position, in which the operator's speaking set 16 is connected to the calling line and the relay 70 is energized. Operation of indicating-device. When the interrupter 110 next closes its contact, the relay 71 is energized and locks up in series with the relay 73 under control of the relay 70. The circuit 60 connected to the identifying-means is thus extended to a relay 72, which repeats the first impulse to a relay 76. As soon as the impulse ceases, the relay 76 locks up through a relay 77, which brings the next relay 78 under the control of the relay 72. A second impulse over the circuit 60 energizes the second pair of relays 78, 79, opening the holding-circuit of the relays 76, 77. A third impulse energizes the relays 80, 81, opening the holding-circuit of the relays 78, 79. One, two, or three impulses from the identifying-device 13 thus cause the energization of the first, second, or third pair of relays, thus preparing the circuit of one of the lamps 82, 83, 84, which lights up when the relay 96 is energized by a relay 75 which responds to an impulse from the interrupter 109. The relay 75 locks up under the control of relay 70, and the relay 96 brings the second group of relays and lamps under the control of relay 72, so that the second group of impulses from the identifying- device causes one pair of the relays 87 - - 91 to be energized. The corresponding lamp 92, 93, 94 lights up when the relay 74 is energized by the next impulse from the interrupter 110. The relay 74 locks up under control of relay 70 and opens the circuit of the relay 72 so that further impulses over the circuit 60 are prevented. As long as the relay 70 remains energized, one of the lamps in each group glows, indicating the character of the line and the nature of the service to which it is entitled. By depressing the listening-in key 180 individual to the connecting-circuit 64, 65, 66, the operator may at any time during the connexion bring the indicating-device under the control of the identifying-means and thereby ascertain the character &c. of the calling line. Automatic control of metering and coin-collecting currents. The relays 88, 90, corresponding to the metering and coin-collecting signal lamps, control relays 85, 95 which are associated with self-locking relays 196, 192 governing the application of metering and coin-collecting currents to the calling-line. If, for example, the calling-line is a measured-service line, the relays 88, 85, 196 are energized when the lamp 93 glows. The relay 196 locks up so as to be independent of the indicating- device, and determines whether a weak or strong battery is connected to the armature of the relay 123, controlled by the charge key 179. Similarly, if the calling-line is a coin-collecting line, the relays 90, 95, 192 are energized when the lamp 94 glows. The relay 192 locks up and connects the coin-collecting current to the front contact of a relay 189, also controlled by the charge key 179. When the operator has set up the required connexion, she depresses her master listening-out key 174, thereby moving the sequence switch 165 into its fifteenth position and opening the circuit of relay 70, which returns the indicating-device to its normal condition. At the end of a conversation, the operator depresses her charge key 179, energizing relays 123, 189. If the line is a coincollecting line, the necessary current is sent to line over the contacts of relays 189, 192, and if the line is a message rate line, the meter 27 is energized by a strengthening of the current in the test lead 64 over the contacts of relays 68, 123, 196. A coin may be returned to the caller in the seventh position of the sequence switch by the depression of the key 124.