US2034883A - Telephone system - Google Patents

Description

, 1936- F. J. SCUDDER' 2,034,883

TELEPHONE SYSTEM Filed Oct. 12, 1933 s Sheet-Sheet 1 INVEN7UR F. J. SCUDOER F. J. SCUDDER I 2,034,883

/ TELEPHONE SYSTEM Filed Opt. 12, 1933 5 Sheets-Sheet 2 lNl/ENTOR F J. .SCUDDER F. J. SCUDDER TELEPHONE SYSTEM Filed Oct. 12, 1933- I5 Sheets-Sheet 3 lNl/ENmR 4 F J SCUDDER Patented Mar. 24, 1936 UNITE TELEPHONE SYSTEM York Application October 12, 1933, Serial No. 693,265

18 Claims. (01. 179-22) This invention relates to telephone systems and particularly to small capacity automatic telephone systems.

An object of the invention is to provide im- 5 proved and economically arranged systems for automatically establishing connections between telephone lines by means of a single switching unit of the cross-bar type.

Another object of the invention is to increase 10 the capacity of such switching units.

Heretofore systems have been provided in which a single cross-bar switch has been employed for establishing connections from one line to another in a single switch. A system of this 15 kind is shown in a patent to L. R. Waller 1,567,309

of December 29, 1925. The copending application of Carpenter and Clark, Serial No. 693,287, filed on even date with the present application,

now Patent No. 1,991,193, granted Feb. 12, 1935,

20 also shows an arrangement of this kind in which links are used, each comprising a line finder branch and a connector branch with means whereby the lines terminate at the cross-points or" separate horizontal rows and the link branches 25 terminate in individual vertical rows of crossconnecting points. A calling line is connectable with the line finder branch of an idle link and the called line with the connector branch or this link.

30 A feature of the present invention is a system of this general type in which the calling or called lines terminating in the switch may be called horizontal lines and be arranged in pairs, each pair terminating at the cross-connecting points 35 in an individual horizontal row; and in which connecting branches or lines may be called vertical lines and be arranged in pairs, each pair terminating at the cross-connecting points in an individual vertical row, and in which two '40 pairs of. such vertical lines are connectable to a single link. The arrangement is such that a calling horizontal line may be connected to the called horizontal line through a vertical line of an idle pair, the associated link and another ver- 45 tical line of the associated pair. One embodiment of this invention, therefore, contemplates the use of two groups of contact sets at each cross-connecting point for the connection or" two horizontal lines with two vertical lines so that a call in- 5 coming on one of a pair of horizontal lines may be extended through vertical lines of a line finder pair through the associated link and one vertical line of a connector pair to the called horizontal line of any pair.

I 55 A modified form of this system contemplates groups of vertical lines arranged with one line finder vertical line and two connector vertical lines in each of a plurality of groups and a plurality of other groups arranged with two line finder vertical lines and two connector vertical lines in each group. The horizontal lines may in this case be arranged so that one horizontal line of each pair normally has access at cross-connecting points to the single line finder vertical line in one group and the other horizontal'line of. each pair normally has access at cross-connecting points to the single line finder vertical lines of another group, and so that if a calling line of any pair of horizontal lines finds the associated single line finder vertical line busy, the call is transferred to the groups having two line finder vertical lines where a connection may be established through the associated link through one of said line finder vertical lines.

This invention has been illustrated in the accompanying drawings in which Figs. 1, 2 and 3 arranged according to Fig. 4 show one embodiment of the invention, and in which Fig. 5 shows diagrammatically a modified form of the invention. An ordinary cross-bar switch of the type disclosed in Patent 1,168,419 to J. N. Reynolds of January 18, 1916, may be employed and has been illustrated in diagrammatic form at S. This switch may be arranged for a number of lines I to 8 and 9 to It terminating in the switch at cross-points in contact sets arranged in horizontal rows. Lines l, 2, 3, l and 8 and 9, II), ll,

15 and It only have been shown and may be termed horizontal lines. At each cross-point in a horizontal row the contact sets of two lines are shown, for example, lines I and 9 are shown terminating at contact sets 20 at one cross-point and at 2i at another cross-point in a horizontal row and so on. The contact sets of these lines have access at various cross-points to contact sets associated with links such as A and B, each comprising four lines each of which may be termed vertical lines. The calling lines have access to the branch or vertical lines Al of. link A or Bl of link B and the called lines have access to the branch A2 of link A or B2 of link B. For example, lines- I and 9 have access through the contact set 20 to branch Al if they are calling lines and if they are called lines they have access through contact set 2| to branch A2. If line l is calling a connection is made, for'example at contact set 29 of branch AI and then through these contacts through the group of conductors 23, while if line 9 had been a calling line this line would have access through contact set 20, 5

lines through either set of conductors 23 or 24 s and for called lines through the set of. conductors 25 or 26 and corresponding contact sets of the cross-bar switch. In case, however, this link is:

in use, the connections will. extend through .the

other link B or even through other links if link B is busy. In the cross-bar switch, no such link has been shown but certain relays individual to one such link have been shown at CF. Similarly, certain relays individual to link B have been shown at BE while the complete circuit arrangement and relays for the link A has been shown at AD. The relay and circuit equipment common to all links has been shown at G. The horizontal operating magnets for connecting the lines to the links have been shown as follows. The magnets for lines I and 9 at SI, for lines 2 and IE3 at S2, for lines 3 and II at S3, for lines I and I5 at S! and for lines 8 and I6 at S8. The vertical operating magnets have been shown at 28 for branch Al, at 23 for branch A2, at 30 for branch BI, and at 3| for branch B2, while the remaining vertical operating magnets for other links have been omitted.

It should be understood that the operation of one horizontal magnet and the operation of one vertical magnet and the release of the operated horizontal magnet causes a connection to be established between a line and a branch of an idle link at the corresponding cross-point and from thereon over either set or branch23 or 24 for calling lines and over either set or branch 25 or 26 for called lines if a connection is made over the link A.

. A description will now be made of the operation of the above mentioned system while establishing a connection from a calling line I to a called line 2 over the link A.

When the calling subscriber of line I lifts his receiver from the switchhook a connection is established through the subscribers loop in the usual mannerfrom ground at contacts of cut-01f relay 32 over the subscribers loop and back over contacts of the same relay 32 through a winding of line relay 33 to battery at the contacts of relay 34. Relay 33 operates and closes an obvious circuit for the operation of the horizontal magnet SI for the subsequent operation of the set of contacts 20 and 2| or other contact sets in the same horizontal row. If line 6 had called line relay 35 would have operated and in that case in addition to the operation of. the horizontal magnet SI, relay 36 would have operated over a circuit from battery through the winding of magnet SI, contacts of line relay 35, winding of relay 36 to ground. This relay 36 in operating would eventually cause the operation of relay 3! to switch from the group of conductors 23 to the group of conductors 24 to establish a connection from line 9 through the conductors 24 to the common equip- .ment AD. In the present case, however, these of relay 38, contacts of the intermediate line relays such as 42, 43, 44 and 45, a winding of relay 33 to ground. Relay 34 in operating opens original energizing circuit for relay 33 and closes a circuit for the operation of relay 5!] in the equip- .ment AD from battery through the winding of this relay, contacts of relay 5|, key 52, contacts of relay 34, contacts of relay 53, to ground at contacts of the vertical magnet 29.

. Relay 56 causes the operation of relay 54 from battery through a winding of this relay, contacts of relay-5B to ground. Relay 54 would now close a circuit for the operation of relay 3'! due to the operation of. relay 35 in case line 9 had called. In this case, of course, this circuit is not closed as line I is the one calling. Relay 54 closes a holding circuit foritself to ground at relay 40.. Relay 53 also closes a holding circuit for relay' 34 independent of relay, 38 to ground at relay 68. This relay 56 further closes an obvious circuit for relay 55 and this latter relay in operating closes obvious circuits for relays 56 and 39. Due to the operation of relays 56 and 39, a circuit is completed from the dial tone source at 59 (not shown) through contacts of relays 53, 39 and 6|. To one of the conductors of the group 23 for transmission to the calling subscribers line when the vertical magnet 28 is operated to close the connection through contact sets 2 5. It will be noted that the operation of relay 55 closes a circuit for this vertical magnet 28 from battery through the winding of this magnet, contacts of relay 64 to, ground at contacts of relay 56. Magnet 28 in operating now closes the connection from conductors 23 to line I through the contact set 26 of the cross-bar switch in the usual manner. The operation of magnet 28 closes a holding circuit over the tip and ring conductors of the group 23, contacts of relay 3?, the two windings of the pulsing relay 66 to battery and ground. Dial tone is now also transmitted through the contact set 26 to the calling subscribers line and relay 66 is operated through the calling subscribers lay 66 closes an obvious circuit for the operation of relay 61 and this relay in turn an obvious circuit for the operationof. relay 68. Relay 53 in operating closes a circuit for maintaining relay 34 operated from battery through the winding of this relay, contacts of relay 54, contacts of relay 68 to ground so as to maintain the original energizing circuits for all line relays open and thereby prevent other lines from calling until the common relay and circuit equipment is freed from use in connection with link A. It should be noted that on the energization of relay 39, the circuit for relay 38 was opened so that the original energizing circuit for relay 34 was opened, but

for relay 31 but as this relay is not operated, this loop over the circuit hereinafter mentioned. Re-

this will 'not take place until after relay 68 has operated as relay 55 is slow in operating and relay 38 is slow in releasing. Relay 38 in releasing opens the locking circuit for the line relay 33 which in releasing causes the release of the horizontal magnet SI. The vertical magnet 29 holds the connection through the switch S. It should also be noted that on the operation of relay 39, a circuit was completed for the slow to operate relay I9 which may be of the dash-pot type from battery through the winding of. this relay, contacts of relay 39, to ground at contacts of relay 59. The purpose of theoperation of this relay is to free link A from the calling subscribers line if the calling subscriber fails to dial within a certain period. The circuits are now in condition for dialing.

When the calling subscriber now dials he will on the first impulse cause the release and reoperation of the pulsing relay 66. On the release of relay 66 a circuit is completed for the operation of relay I2 from battery through a resistance, winding and make-before-break contacts of relay I2, contacts of relays 39, 66 and 68, contacts of the vertical magnet 29, and contacts of relay I9 to ground. Relay I2 in operating closes the locking circuit for itself toground at relay 59 and causes the operation of the first horizontal magnet SI as follows: from battery through the winding of magnet SI, contacts of relay 53, contacts of relay I2 to ground. Relay 6! remains operated during the pulsing due to its slow to release characteristics. When now the pulsing relay 66 is again operated at the end of the first impulse, the shunt circuit for relay I3 is opened at contacts of relay 66 so that a circuit completed for the operation of relay 13 by the relay l2 becomes effective. This circuit may be traced as follows: battery, a resistance, winding of relay l3, contacts of relay I2, contacts of relay 39 toground at contacts of relay 59. The operation of relay l3 closes an obvious circuit for the operation of relay 53 and an obvious locking circuit for the horizontal magnet SI. It should be noted that the original energizing circuit for magnet SI is opened by the operation of relay 53. Relay 53 also closes. a locking circuit for itself and a circuit for the operation of relay I5. The locking circuit extends from battery through a winding of relay 53, contacts of relay 53, contacts of relay 39 to ground at relay 59, and the circuit for relay I5 extends from battery, winding of relay I5, contacts of relays 53, 39 and 59 to ground. Relay 53 also opens the circuit from the dialing tone source 59. When now the pulsing magnet 66 releases in response to a second impulse, relay I2 is released due to a shunt circuit established-at the right-hand armature and back contact of relay 66, from battery, a resistance, contacts of relays I3, 39 and 66, and 68, contacts of magnet 29, and contacts of relay E9 to ground. The release of relay I2 closes a circuit for the second horizontal magnet S2 from battery, winding of this magnet, contacts of magnet SI, contacts of relay 53, contacts of relay I2 to ground. When relay 66 is again actuated at the end of the second impulse, relay I3 is released as the original energizing circuit for relay I3 was opened on the release of relay I2 and the holding circuit established for relay I3 through the make-beforebreak contacts of relay I2 to ground supplied through the right-hand armature and back contact of the impulsing relay 66 is opened by the release of this relay. Magnet S2 provides alocking circuit for itself on the release of relays 12 and i3 through contacts of these relays, contacts of relays 53, 39 and 59 to ground, while the locking circuit for magnet SI is opened on the release of relay I3 so this magnet will; now release. As no further impulses are transmitted, the circuits now remain in this condition. It is evident therefore that relays I2 and 13 will be operated and released by alternate impulses in such a manner that on the third, fifth and seventh impulses, relay I2 will operate to close the circuits for S3, S5 and S1 magnets and on the fourth, sixth and eighth impulses relay I2 will release to operate magnets S4, S6 and S8. The original energizing circuit for relay 59 was opened on the energization of relay 53, but this relay 59 was maintained operated during the pulsing over the circuit from battery through the winding of relay 59, contacts of relays 54 and 68 and the ground supplied during pulsing at a back contact of relay 66 as relay 59 is slow in releasing, as the pulsing ceases, relay 59 is allowed to release. Relay 59 now causes the operation of the vertical magnet 29 from battery, winding of this magnet, contacts of relay 56, which is still maintained operated due to the slow to release characteristics of relay 55, contacts of relay 59, contacts of relays 39, 49 and M and the contacts of magnet S2 to ground. Another relay operated by the release of relay 59 is the relay 5| from battery, winding of relay 5, contacts of relay I6, of the link CF, contacts of relay 56 to ground at contacts of relay 59. Relay 5| is locked in operated position mechanically by the armature of relay I8, as indicated in schematic form. Relay'59 being released to open the original energizing circuit for relay 54 and magnet 23 being operated causes relay 54 to release and this relay in releasing causes the release of relay 34. After an interval relays 55 and 56 are released. The release of relay 55 also causes the release of relay 39 and this relay in turn causes the release of relays 53, magnet S2 and relay I5. The common equipment S is therefore now returned 45 to common use for other cells over the other links" BE and CF.

Returning now to the operation of the magnet 29, this magnet in operating closes a connection between the called subscribers line 2 at contact. 0 89 of the cross-bar switch and the set of con-" ductors 25 to contacts of relay 8|. It should be noted that on the closing of the connection through contact set 89 relays BI and cut-off relay 96 are operated over a circuit from battery, windsing of the cut-01f relay 94, contacts 89, the sleeve conductor of the group 25, a winding of relay 6|, contacts of relay 56 to ground at contacts of relay 68. This takes place of course before relay 56 has time to release. Relay 94 in operating disconnects the called subscribers line from ground on one lead and from the connection to the line relay 42 for the other lead. Relay 6| in operating closes a holding circuit for itself to ground at contacts of relay 68. Relay 6I in oper ating also closes a circuit for holding vertical magnet 29 operated and another circuit for the operation of relay 82 from battery to the winding of thisrelay, contacts of relay 64, contacts of relay 6|, contacts of relay 56 to ground at contacts of relay 68. This also takes place before' relay 56 has time to release. Relay 82 in oper ating establishes a locking circuit for itself to ground at relay 69 over contacts of relay 95. The operation of relay 82 establishes a conne tion between the tip and ring conductors of the .called subscribers line, the tip and ring conductors of group 25, contacts of relay 82, the ringing trip relay 85 to the ringing source at'86 for onelead and to ground at contacts of relay H 82 for the other lead. This rings the called sub- 8 through condensers 83 and 96 through the tip and ring conductors' throughits contacts to bat- .tery and-ground through the winding of relay 88.. Tip and ring conductors from the called line are now also extended by the operation of relay and ring :conoluctors, contacts of relay 3! and contacts 26 to the callingsubscribers line I sothat conversation can now take place. Talking battery for the calling line is furnished through the windings of impulse relay 66 and talking battery for the called line through the windings of relay B8.

- When thecalling subscriber replaces his receiver on the switchhook after the conversation is finished, relays-66,51 and 68 are reelased. Relay 68 causes the release of magnet 28 and. relays GI, 64 and 88 and opens the original energizing circuit for relay 5i. Relay 6! releases magnet 29. The connection between the two subscribers is therefore now released. Relay-5l is not released as it is-being mechanically locked by relay 18.

In regard to the allotting of the links A, B and C for use in establishing connections the following explanation may suifice. The link A is allotted first, link B second and link C third.

If link C is engaged and links A and B are idle link A is allotted first. It should be noted that through the winding of this relay, contacts of when a connection has been established for example through link A relay Si is operated. A

second connection may now be established through link B as :relay39 is released. Therefore, if-the calling line operates its corresponding horizontal magnet a circuit may be completed for the operation of relay 38 from battery relay 39, contacts of relays 39-13 and 39C to ground at the contacts of the operated horizontal magnet. From this point on the operations of the circuits are exactly the same as heretofore described except that the operation of the relay '58-B in link B is operated from battery through the winding of this relay, contacts of relay 5lB,

contacts of the operated relay 5|, contacts of relays 34 and 53 to ground at the vertical magnet of link B corresponding to vertical magnet'3l J60 of link B.

After a connection'has been established through link B a circuit connection may be established through link C as the relays 56 and Sil-B in links A and B are released and the operations of the circuits in link C are exactly the same as heretofore described in connection with link A, except that in this case the relay 5il-C of link is operated through contacts of the operated re-" tion of relay Eli-C and that when the connection 50C was released before relay 56-C was re- If now link C should be engaged and links A and B released it should be noted that the special I relay 16 in link C-has operated due to the opera- --on1y operates a considerable interval after it is through link C was established and the relay leased a circuit-was completed-for the operation of relays118 and:18B so that now-relays-l and 5lB.may be unlocked to. return links A and B for seizure. If another call now comes in the link A will be the one to be first usedas its 5 relay 50 will operate due to the released condition of its relay 5|. As soon as the connection throughthis link A has been completed the release of relay56 and before relay56 is released will complete a circuit for the momentary operation; of relays l8 and 18-B as follows: From battery, windings of these relays in-parallel, contacts of ,theoperated relay 16, contacts of relay 56 to ground at relay 50. The purpose of this momentaryoperation of relays 18' and l8 -B 515 in this case to permit the'release of relay 5|"B in case link B has been engaged and released 7, in themeantime; :The operation of relay. 18 will, of "course; in'thiscase have no'efiect'asrelay 5| will be heldoperated by relay 68.. Therefore, if '2 v, link B isnow idle'and links A and C are engaged,

of line relay 35;" Relay 36 in this case causes the I operation of relay'3l to switch the connection from the contact group 23 to the contact group 24 thus establishing a connection from line 9 to the contact set 26. Relay 3! is locked by magnet 28; If now the called line is one of the group of lines 9 to I6 the connection is switched from the conductors' 25 to 26 through a contact set, such as'80. -In this case the calling subscriber must dial two digits; The first digit must always be nine and the second digit any one of the digits one-to eight depending on which of the lines 9 to IE is wanted. Consequently, the first digit will operate in succession all of the magnets SI to S8, and on the ninth digit relay I 00' is operated from battery, winding of this relay, con- 7 tacts of magnet S8, contacts of relay 12 to ground. Relay 106 in operating then closes a connection from the operation of relay 8i from battery, winding of this relay, contacts of relay 54, contacts" of relay I00 to ground. Relay 8| locks to ground at contacts of relay 68. This accomplishes the switching of the connection for the called line to conductors 26. At the end of the ninth impulse relay 12 releases causing the release of relay I06 and relay 5!] being held during. pulsing releases in the normal manner. Ordinarily if any of the magnets SI to S8 had been operated the vertical magnet 21 would have operated as a result of the release of relay C-from a ground at contacts of any one of these magnets. As this 5 does not take place the net result of dialing nine is that-relay 8| only is operated. The second digit may, therefore, now be dialed and in the same manner as-hereinbefore described a desired horizontal magnet may be selected. For example,

ductors 26 willbe extended'through contact set -86 to line l2. Otherwise,-the operations are the same as hereinbefore described.

'70 Referring now to the operation of relay 10, this is a slow-acting relay of the dash-pot type which energized. The purpose of this relay is to release the common equipment D forthe use of otheri calls if the calling subscriber that has appropriated link A does not dial within this interval of time. If this is the case relay 10 will operate and thereby attract its armature and remove the ground connection for the pulsing circuit controlled by relay 66. Relay 10 will also close an obvious circuit for the operation of relay 53. This relay in turn opens the circuit for relay 50 which in releasing releases relays 55 and 56. It should be noted, however, that the vertical magnet 28 is maintained operated by a ground connection established through contacts of relay 68 which remains operated. The original energizing circuit for this magnet is opened on the release of relay 56. As long as the calling subscriber has his receiver ofi the hook the link A will be held occupied, but the calling subscriber cannot dial while the common equipment G may be used by other calling subscribers in establishing connections through links B or C if idle.

A modified form of this system has been shown in Fig. 5 in diagrammatic form. In this arrangement three links have been shown terminating in the contacts in the cross-bar switch S for "lines I and 9, and 8 and Hi. The link A in this case is only provided with one line finder branch so that at the cross points where contacts of this branch terminate lines I to 8 only have access to this branch. Similarly, the link B is shown with a single line finder branch. To this line finder branch lines 9 to 5 only have access at the cross point while link 0 is equipped in the same manner as the regular link shown in Figs. 1 to 3. The arrangement, therefore, in this case is such that lines I to 8 will normally use link A and lines 9 to [6 link B and if these links are busy link C will be used by either group of lines.

What is claimed is:

1. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines arranged in pairs, each pair terminating at cross-points of an individual horizontal row, vertical lines arranged in groups, a

, link for each group of vertical lines, and means for establishing a connection from any horizontal line to any other horizontal line through a link and two of the vertical lines associated with said link.

2. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines arranged in pairs, each pair terminating at cross-points of a separate horizontal row, vertical lines arranged in groups, each group terminating at cross-points of two vertical rows, links, each link capable of connecting two vertical lines of a certain group with one vertical line terminating in each of the two vertical rowsof cross-points of said group, and means for establishing a connection from a line of a pair of horizontal lines through a link and two of the group of associated'vertical lines-to either one of any ;having a plurality of cross-connecting points,

horizontal lines arranged in pairs, each pair terminating at all cross-connecting points of an individual horizontal row, vertical lines arranged in pairs, each pair terminating at all cross-points of an individual horizontal row, links each connectible to two pairs of vertical linesand means for establishing a connection from either line of a pair of horizontal lines through a corresponding line of a pair of vertical lines over the link connectible to said pair of vertical lines and over either of the other associated pair of vertical lines to a corresponding line of a pair of horizontal lines.

4. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines, vertical lines, means at each cross-connecting point for connecting either of two sets of lines together each set comprising a vertical and a horizontal line, links, and means for connecting either of two vertical lines terminating at one row of cross-connecting points through a certain link to either of two vertical lines terminating at another cross-connecting point.

5. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines, vertical lines arranged in pairs, links each associated with two pairs of vertical lines, and means for establishing a connection from any horizontal line to any other horizontal line through any link and over one vertical line of each of the two pairs associated with said link.

6. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines, two groups of vertical lines, links, means for connecting any horizontal line to any other horizontal line through a link and two .vertical lines one from each group and at two crossconnecting points one for each group of vertical lines.

'7. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines arranged in pairs, two pairs of vertical lines, a link associated with said two pairs of vertical lines, means for establishinga connection at each cross-connecting point between either horizontal line of a pair and a corresponding vertical line of one pair and. between either horizontal line of a pair and a corresponding vertical line in the other pair of vertical lines,

and means for establishing a connection over said link between either vertical line of one pair and either vertical line of the other pair.

8. In a telephone system, a cross-bar switch having a plurality of cross-connecting points, horizontal lines, vertical lines, links and means for establishing a connection from any calling horizontal line to any other called horizontal line through a link in one direction only and through one vertical line in one direction and another vertical line in the other direction including a connection at a cross-connecting point between the calling horizontal line and the first mentioned vertical line, and a connection at another cross-connecting point between the second mentioned vertical line and the called horizontal line, and means at each cross-connecting point for establishing either of two such connections between a calling horizontal line and a called horizontal line.

9. In a telephone system, a cross-bar switch having two sets of contacts at each cross-connecting point, a group of horizontal lines, a group of vertical lines terminating in the contacts of one set at the cross-connecting points, another group of horizontal lines, and another group of vertical lines terminating in the contacts of the other set at the cross-connecting points, links and means for establishing a connection from a horizontal line of either group through a contact set and a vertical line of the corresponding group through a link and to another contact set and another vertical line in another group to another horizontal line in the corresponding group.

10. In a telephone system, a cross-bar switch havingtwosets of contacts at each cross-connectlishing connections at the contact setsbetween horizontal. calling lines, vertical lines for establishing connections at contact sets to horizontal called lines, links, means for connecting a calling horizontal line through one contact set and associated. vertical line and a link through another contact set and a vertical line to an associated 1O called horizontal line.

11.. In a telephone system, a cross-bar switch having'two groups of contact sets at each crossconnecting point arranged in horizontal and verticallrows, a pair of horizontal lines for each Lhorizontal .row, of contact sets, a pair of vertical lines !for each vertical rowof contact sets, each horizontal line in a pair terminating in different group of contact sets at each cross-connecting point and each vertical line in a pair terminating in a differentgroup of contact sets of each crossconnecting point, a link for each two vertical rows of ,vertical lines, and means for establishing a connectionfrom any horizontal line. to another horizontal .line. at..the. corresponding contact.

.groups at the twolcross-connecting points of two vertical rows of vertical lines and the. correspond-, ing link, a

12. In a telephone system,,a cross-barswitch having two groups of contacts at each OIOS-COU:.

.-.necting .point ,for .the establishing of .two, inde.-. pendent cross-connections of intersecting. lines,

horizontal. lines divided-into pairs, vertical lines divided; into pairs horizontal- .magnets one. for

each pair. of horizontal lines, vertical magnets,

05 ioneiorreach pair of vvertical lines, a link for each two. pairs of vertical lines, means, including the actuationof a horizontal magnet and, .a vertical magnetionestablishing a connection between a painofhorizontal lines one of which is a. calling linezanda pair of vertical lines .,and for establishing a connection from saidcalling line and one of said pair of vertical lines to one end of theassow ciated link, and means includingthe; actuation of another horizontal magnet andmanother vertical amagnet for establishinga connection between. a pair of horizontal lines one of which is the called line and ,anothenpair of vertical lines, and for establishing a connection from said calledelineto' the opposite end of said link. mi 13. Inga telephone system, a cross-bar. switch having two groups of contacts at each crosseconnecting point for the establishing of .two..independent cross-connections of intersecting lines,

horizontal lines divided into pairs, vertical lines :clivided into pairs; horizontal magnets; .oneior each pair of horizontal lines, vertical magnets, one-'for each pair-of vertical lines, aelink-for. each two pairs-of vertical lines, means including the actuation-of a horizontal magnet and a vertical- .-magnet for establishing a connection between a pairof horizontal lines one of which is a calling lineand apairof vertical lines and for establishing a connection from said calling lineand one of said pair of vertical lines to one end of the :link; andmeans responsive to impulses received which-is thecalled line and thetwolin'es of .an--

othenpair of vertical lines, and :for establishing a connec-tion'throughsaid called line over one-of said verticallines from the other endiof said link:

14.;In a telephone system, a cross-bar; switch ciatedwithi'the link used and for establishing-a 1 links associated with groups of four vertical lines;

having a plurality of--cross-connecting::points; ing point, horizontal lines, vertical lines for estabhorizontal lines arranged in pairs, two'pairs of vertical lines, a link associated with said two pairs of vertical lines, means for establishing a connection .at each cross-connecting point between .5 either, horizontal line of a pair and a corresponding .vertical line of one pair and between either: horizontal line of a pair and a corresponding ver--- tical line of the other pair of vertical lines, a reflay for each, pairof vertical lines, and meansr. -10. responsive to the connection of a particular ver-.-. tical line of either pair-of vertical lines to-a hori-....- zontal line for operating. the associated. relayto: connect said vertical line to the-link.

15. In a telephone system, a cross-bar SWitChl5;,,-. having ;a plurality of cross-connecting points, horizontal lines arranged. in pairs, two-pairs of, vertical .lines, a link normally connected to one. vertical line of .:each pair, means for establishing. a connection at each cross-connecting point. be-a 20w tween either horizontal line-of a pair anda corresponding .vertical line of one. pair-and between either horizontal line of a pair. and a corresponde.W ing vertical line of the other pair, of vertical lines a relay. for. each pair of vertical lines, and. means-:25.- responsive-to the, connection to a horizontal elinea. ofrthe vertical line of either pair normallyoise connected ,from the link forloperatingethe assoiciatedrelay to disconnect the-normally connected I, verticallline.fromr-thellink and connect the more-.301:- mally disconnec ted:vertical lineto the-link;

16.1 In a telephone system a cross-bar -switch having a plurality-- of cross-connectingnpoints horizontal lines arranged in pairs, eachJ-pair ter-:

.. minating at cross-points of an individual horizon-= 35 tal row verticallines;somearrangedein groups of four linesand othersarranged in groups of three a? lines, a link for each group of -vertical lines-and means for-establishing'a connection -from-any horizontal-dine -.to anyother horizontal dinem through alink, andtwo of the vertical lines asso-q ciated-with said link;

1'7..- In'a telephone: system'a cross-bar. switchw having a plurality of cross-connecting -points,-

- horizontal lines arranged in pairs,:each"pair tormi-nating'at:cross-points of an individual horizontal row; vertical lines, some arranged in groups-"1 of four lines and others arranged in groups of--* thr'ee-li-nesg-a link;for each group:of vertical lines, means for establishing'aconnection from anyone of certain horizontal lines to any. other horizontal linathrough certain of the links associated With..' groups .of three vertical lines,.theconnection-bee ing;established.:.over two :of the vertical lines assoe connection from'any oneof certain other 'hori-i zontalilines'toany other horizontal line through I certain;other of :the links associated with: the

groups of three vertical lines, the connection bex' ingestablished over two of the vertical lines asso-' ciated with thelink usedanct means for estab-i lishing a connection from any horizontal line to' 1 any other horizontal .line .through" any of :the

the connection being established over two of the verticallin'es associated with the linkused;

18. Inra telephone system a cross-bar'switchi:- having 'a plurality of cross-connecting"-points;

-- horizontal lines arranged in pairs, each pair tor-- minatingat cross-points of an'individual horizontal row; vertical lines arranged in'groups, some groups comprising'three vertical lines with-one- I lineterminating at cross-points. of -,one' vertical rowaand theother tWo linesterminatingat cross-.17

points of another vertical row and some groups comprising four vertical lines with two lines terminating at each of two vertical rows of crosspoints, a link for each group of vertical lines, the links for the three line groups being capable of connecting the single vertical line of one vertical row with either of the two lines of the other vertical row of the associated groups and the links for the four line groups being capable of connecting either vertical line of one vertical row with either vertical line of the other vertical row of the associated groups, means for establishing a connection from 'one of the lines in each pair of horizontal lines to a link associated with certain three line groups of vertical lines from the single vertical line in a group to either one of any pair of horizontal lines over an associated vertical line of the other two lines in a group, means for establishing a connection from the other of the horizontal lines in each group in each pair to links associated with certain other three line groups of vertical lines from the single vertical line in the group to either one of any pair of horizontal lines over an associated vertical line in the other two lines in the group, and means for establishing a connection from a line of any pair of horizontal lines through a link associated with the four line groups of vertical lines over two of the group of associated vertical lines to either one of any pair of horizontal lines.

FREDERICK J. SCUDDER.

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