Patent GB-190516024-A (GB)
Title: Improvements in and relating to Telephone Office Systems and to Methods of Establishing Connections therein.
Inventor: LEAN CLEMENT
Filed: 1905-08-04
Granted: 1905-11-23
Abstract: 16,024. Lean, C., [Deutsche Telephonwerke R. Stock & Co.]. Aug. 4. Telephone systems.-Three groups of operators are employed at a telephone exchange, namely, at the distributing office, the enquiry office, and the connecting office; the first office receiving a call signal at once connects the subscriber to an unoccupied operator of the second group, who enquires the connexion required, and then orders an unoccupied operator of the third group to make connexions first with the multiple socket of the subscriber to be called and then with the proper enquiry plug, which has been connected at the first office to the calling subscriber. The three offices are indicated in the Figure by A, B, C, respectively. The subscribers' wires a, b and a<1>, b<1> traverse in multiple the connecting office C and terminate each in a single socket 8 in the distributing office A. When a subscriber calls, his lamp 11 lights up, and an operator at A inserts into the socket 8 an enquiry plug 1 belonging to an unoccupied operator at B. The lamps 15, 16 indicate if alight that the corresponding operator is unoccupied. The removal of the plug 1 from its place causes the closure of the contact 17 through the lamp 20 at the enquiry office and the the coil 21. This coil breaks the contact 22 and puts out the lamps 15, 16. The operator B, noticing the lamp 20, pushes down the corresponding switch 13 and forms a speaking-circuit with his set 23 and the calling subscriber's apparatus through the plug and jack 1, 8. Having learned the connexion required, the operator B releases key 13, and presses down the order key 14 which connects his speaking-set 23 with the set 42 of an unoccupied connecting-office operator, lamps 25, 26 being his guide. This operator C is then informed of the number of the connexion required and the number of the plug line 6, 7 to use. Meanwhile, the key 14 has closed the switch 24, energizing the coil 27, opening the contact 28, and extinguishing the "unoccupied" lamps 25, 26. The operator C inserts a plug 3 into the nearest socket 4 of the wires 6, 7, which are connected in multiple through the sockets 4, 5 of the connecting operators. This action closes the contact 52, and by shunting the coil 18 extinguishes the lamp 20 and relights the lamps 15, 16, indicating at the office A that this enquiry operator is once more unoccupied. The operator C makes the " busy " test as usual with the plug 2, and if the connexion desired is engaged informs the subscriber, and then presses the key 30, energizing the coil 31 at the station A and closing the contacts 32, 33, thus lighting and keeping alight the final signal lamp 34. The operator A then disconnects the plug 1. If the connexion desired is not engaged, the plug 2 is inserted into it, say the jack 29, and the speaking- switch 35 is brought into calling position. In this calling position and in the testing but not in the through speaking position, the switch 36 is closed, opening the contacts 39, 40, 41. When the contact 39 is opened, the lamps 25, 26 are once more extinguished, indicating that the corresponding order wires cannot be employed. When the conversation is finished, in addition to the lamp 45 at C being lighted, the final signal 34 can be lit by pressing the key 30. Although the connexions may then be broken at the connecting office, the lamp 34 glows till the enquiry plug 1 is replaced in position.