Patent GB-149936-A (GB)
Title: Improvements in or relating to telephone systems
IPC: G07C1/20
Filed: 1920-04-06
Abstract: 149,936. Automatic Telephone Manufacturing Co., (Assignees of Grauel, E. L.). Aug. 20, 1919, [Convention date]. Automatic exchange systems and apparatus; party-line systems and apparatus; repeating systems.-In a supervisory system for watchmen or like purposes for association with a telephone system, the removal of any one of the instruments of the telephone system gives a visual indication of the number of the telephone used, and automatically records its number and time of use. Other supervisory arrangements are also described in connexion with the preferred application in which the supervisory system is associated with a a private automatic exchange system connected to a public manual exchange, the incoming lines from which terminate at a gateman's office, the gateman answering incoming manual calls and establishing outgoing manual calls. Any automatic subscriber, however, may call a special number, such as 97, which will connect his line across No. 97, Fig. 2, and energize relay 20 to connect bridge 21 across the outgoing manual line and signal the manual operator. Substations as 24, 25 which are used for watchmen's reports, are connected to a special number as 04, 05 which permits the gateman to listen in on these lines whether busy or idle, the special numbers having no connexion from their test contacts to the regular test circuit of the various lines, but only having a connexion from their test contacts through a relay to battery. Instead of this arrangement, the gateman may be given a special listening-in connector which will seize the regular lines whether busy or idle. When a watchman calls from line No. 24, for instance, the line relay closes momentarily a circuit over conductor 13 to operate the visual indicator C in the gatehouse, and the recording clock B located in an official's room. The indicator C contains a signal for each line, each signal comprising four magnets 3, 4, 5, 6, and an armature 7 pivoted at its centre, carrying a disk 8 bearing the number of the line in two lower triangular spaces, while the upper triangular space is coloured white or red; white if the line has a special listening number as 04, but in other cases red. The armature 7 normally rests in line with magnets 3 and 4, but when magnets 5 and 6 are energized, the armature moves the disk 8 to expose the numbers and colour through three openings in the cover. All the magnets 3, 4, are connected in series, the gateman resetting all the signals by means of a key K. The clock b has a chart which revolves once in 24 hours and on which each station is allotted a circular space. A magnet is apportioned to each line, and when energized over the conductor 13 pricks the chart in the appropriate space, thus checking the watchmen's reports. The gatehouse attendant is provided with a telephone No. 11 for incoming calls only, which is multipled into the banks of the connector switches without the usual busy guard. He is also furnished with a telephone for in and out regular calls, and a loud speaking telephone in his office is connected to a special number 98, and permits any authorized person to call this number and listen-in to any conversation in the gatehouse. A similar loud speaking telephone No. 99 may be located in any other office for a like purpose. 'The telephone No. 00 is for direct calls to a high official, whose secretary uses the extension No. 88. Ringing current affects the bell of the station corresponding to the number being rung, the bells being connected to opposite sides of the line to ground and the connector sending ringing current over the upper wipers. Both stations are provided with intercommunication buzzers and keys for switching the connexion from one to the other. Jacks J may be installed at various places and' used by initiated persons to call No. 11 or listen-in on various lines. Key K<1> is provided at the gatehouse to control alarm signals throughout the building. When a manual subscriber requires connexion with an automatic station, the gateman may ask the automatic subscriber to call No. 98. If then the telephone of the incoming manual line is placed adjacent to the sensitive telephone 98, conversation may be carried on.