Patent GB-121957-A (GB)
Title: Improvements in or relating to Group Switching Arrangements for Automatic or Semi-automatic Telephone Exchanges.
Inventor: HUETMAN CARL AXEL WILHELM
IPC: H04Q3/42
Filed: 1918-12-24
Abstract: 121,957. Hultman, C. A. W. Dec. 24, 1917, [Convention date]. Automatic and semi-automatic exchange systems.-Relates to systems using switches of large capacity in which group selection is effected by setting in operation finder switches, individual to the desired group, which hunt for the calling junction. In order to prevent wrong connexions when two or more calls are being extended simultaneously, the calling junctions are grouped and the fixed terminals of the finder switches are arranged in groups or rows, each comprising the terminals of a different group of incoming junctions. Each group of junctions is provided with separate group-test-contacts in the different numerical groups of finder switches, so that for a call in a certain group of incoming junctions, this group may be marked as calling only in the finder switches of the numerical group selected, As soon a call occurs on one junction, the other junctions in the same group are marked as engaged until the group-selecting operation is completed. The connectors used are of the type described in Specification 4285/15, and have a capacity of 2000 lines, while two or more group-selecting operations are combined in a single multi-digit group-selecting operation, so that in a system of 99,000 lines, a call can be extended to a wanted line in two numerical steps only, viz., by a multidigit group selector and by a connector. In the semi-automatic system described in detail, calling lines A1, B1, Fig. 11, are connected by linefinders S1 to an operators position provided with registering and controlling equipments set by a common keyboard. The two registers set by the ten-thousands and thousands keys combine to set in motion one or more junction-finders S2 individual to connectors LV of the desired 2000-line group. The junction-finder S2 and the linefinders S1 are switches of the kind described in Specification 121,474, and have a capacity of 1000 lines, divided into two main groups A1, B1, each group having fifty vertical rows with ten lines in each. The wipers of the finders may be moved to the left or right horizontally, and also up or down into one or other of the contact banks. The line-finders S1 are divided into groups of ten, and the junctions FL1 leading from each of these groups are connected to the wires of a vertical row in the contact field of the junction-finders S2. In Fig. 11 two groups of junctions are shown leading to the upper and lower contact fields of the finders S2. Associated with each group of the junctions FL1 is a set of registers RS comprising five registers SOG1, SOG2, SOR1, SOR2, SOR3, set by a hunting movement in accordance with the five depressed keys, and three rotary switches RE1, RE2, RE3 moved by impulses sent back by the connector into positions corresponding to the setting of the hundreds, tens, and units registers. The setting of the ten-thousands and thousands registers determines which numerical group of junction-finders S2 shall be set,in operation, and in order to identify the group of junctions FL1 containing the calling junction, additional group test wires s1, s2, s3 are arranged below the contact fields of the finders S2, the test wire in the wanted group of finders S2 being made operative by the setting of the registers RS associated with that group of junctions FL1. Wrong connexions due to two or more calls being made simultaneously within a group of the junctions FL1 are prevented by the arrangement that when one such junction is taken into use, the other nine junctions in the group are marked busy until the connexion has been established. In order to reduce the number of junctions and finders which are thus marked busy for each call, a group of the finders may be divided into three sub-groups to each of which is allotted a set of registers, and additional test contacts are arranged in the contact bank of the junction-finders to determine in which sub-group the junction-finders search for the calling junction. Construction of switches. The construction of the line and junction finders is identical with that described in Specification 121,474. The rotary switches that respond to the reverting-impulses from the connector are operated by the magnet RE, Fig. 10, and escapement SH, and are returned to normal by the rotation of arms BA carried by spindle VA parallel to the shaft RA The connectors are of the type described in Specification 4285/15. Connexion of calling line to operator's position. When a subscriber removes his receiver. his line relay LR, Fig. 1, starts a series of idle linefinders which operate substantially as described in Specification 121,474, under control of sequence switch SOC to extend the line to a junction FL1 leading to an operator's position, Fig. 2. Operator's position, Fig. 2. Three groups of ten junctions FL1 are allotted to each operator, each group having access to a separate register set, each set being connected to a set of twelve bus-bars 1 - - 12. The three register sets are controlled by a single keyboard. As, previously stated, each register set comprises five switches set by a hunting movement in accordance with the five depressed keys, and three rotary switches moved by impulses sent back from the connector. The five hunting-switches are of the clutch-driven type provided with contacts broken and closed in different positions of the switch, but are shown for simplicity in Fig. 15 as switches with arms moving over contacts. When the junction FL1, Fig. 2, is extended to the calling line, its sequence switch SOC, Fig. 1, is moved into its fourth position, the clearing-relays AR1a, AR1b, Fig. 2, are energized over the calling line, and a call relay RS is connected in circuit with a relav DR, common to the group III of junctions. The relay RS lights a call lamp PL, short-circuits part of its winding (whereby the bus-bar 12 is marked as engaged so that no more relays RS can be energized), and thus increases the current in relay DR, which causes the position sequence switch SOT to rotate to find the group III to which the calling junction belongs. A sequence switch D (only some contacts of which are shown in Fig. 2), individual to the register set III, then moves into position 2, opening contact D1, Fig. 2, so as to flash the call lamp PL showing that the call has been connected through to the operator. The switch SOC, Figs. 1 and 2, is then moved into its fifth position, connecting the calling line over busbars 10, 11 to the operator's speaking circuit 13. The operator then writes down the wanted number on the keyboard, Fig. 3, the depressed keys being held by magnets FE1 - - FE5. The depression of each key earths all the leads to the hunting-switches of the register except the lead corresponding to the depressed key. Referring now to Fig. 15, the ten-thousands register comprises five separate hunting-switches E11 - - E15, each switch being associated with one of the marking-switches E1 - - E5. The thousands, hundreds, tens, and units registers SOF, SOX, SOY, SOZ, each comprise a single hunting-switch F1, X1, Y1, Z1, mechanically connected to the switches F2 - - F4, X2, X31, X32, Y2, Y3, Z2 respectively. When the keys have been depressed, the switches F1, X1, Y1, Z1 rotate to take up positions corresponding to the depressed keys, and as soon as the switch F1 comes to rest, a circuit is closed over contact k and arm F2 of the thousands register to rotate that one of the tenthousands switches E11 - - E15 determined by the setting of the arm F2. The setting of the arm F3 and of one of the arms E1 - - E5 thus determines the 2000-group containing the wanted line. As soon as the registers have all been set, the register sequence switch moves to the third position, in which a circuit is closed over arm F3 and one of the arms E1 - - E5 to start a group of junction-finders individual to the selected group. Operation of junction-finder. This operates substantially in the manner described in Specification 121,474 to extend the calling junction FL1, Fig. 2, to a connector in the desired 2000-line group, except that additional group test contacts controlled by the register are provided, as previously described. The sequence switch SOC, Figs. 1, 2, remains in its sixth position, thereby connecting the connector circuits over contacts C21, C22, C16, Fig. 2, and bus-bars 8, 7, 5 to the. controlling circuits of the register, In Fig. 15, which shows the principal circuits for controlling the connector, the junction-finder is not shown, the leads a, b, d from the connector being shown connected directly to the contacts C16, C21, C22 (compare Fig. 2), from which they are extended to the contacts of the registers F, X, Y, Z. Operation of connector. The numerical wiring of the connector is shown by the numbers inserted in the vertical contact rows of the connector field diagrammatically represented at the bottom of Fig. 15, the upper field representing an even thousand and the lower field an odd thousand, even hundreds being to the left and odd hundreds tn the right of the central normal position of the wipers. Each section of 500 lines is divided into five groups of 100 lines, each group having five vertical rows with twenty lines in each row. The clutch MKVU can drive the wipers to the left and upwards, while the clutch MKHN drives to the right and downwards, these clutches being controlled by relays SRd, SRb, connected to the wires d, b respectively. Impulse-disks driven by the clutch magnets send back impulses over the wires a, b, d to operate the register switches REX, REY, REZ. Assuming that the number of the wanted line is 88837, the switches E, F, X, Y, Z will be set as shown, and from the wiring diagram it will be seen that the wipers must bo moved to the left over four groups to select the group 800-899, and then to the second row in this group, and must then be raised to the eighteenth contact in tho selected vertical row.