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Publication numberUS2301772 A
Publication typeGrant
Publication dateNov 10, 1942
Filing dateJun 1, 1939
Priority dateJun 1, 1939
Publication numberUS 2301772 A, US 2301772A, US-A-2301772, US2301772 A, US2301772A
InventorsBoswau Hans P
Original AssigneeBoswau Hans P
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatic switching system
US 2301772 A
Abstract  available in
Images(4)
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Claims  available in
Description  (OCR text may contain errors)

Nov. 10, 1942. H, P BQswAU 2,301,772

AUTon'rIc swl'rcime s'fsml Filed Jun 1, 1959 4 sheets-sheet 4 INVENTOR. Hans j? Bosa/uw ATTORNEYS.am

Patented Nov. 10, 1942 UNITED STATES PATENT OFFICE AUTOMATIC SWITCHING SYSTEM Hans P. Bosvwau, Lorain, Ohio Application June 1, 1939, Serial No. 276,851

12 Claims.

The present invention relates in general to automatic switching systems, and more in particular to such switching systems as are used for establishing connections between subscribers lines in automatic or semi-automatic telephone systems.

The object of the invention, broadly stated, is to provide a new and improved switching apparatus for use in systems of the foregoing character. which is more economical to manufacture, less subject to trouble in operation, and more economical of space than switching apparatus commonly used for this purpose.

A special object, which is of primary importance in attaining the advantages referred to, is the production of a switching apparatus adapted to serve a plurality of lines and trunks, or groups of trunks of different order, Vinv which the large number of multiple conductors and soldered conu nections previously employed between apparatus units are eliminated. f

Additional features will be pointed out in the course oi the detailed explanation of the invenn tion, and with reference to the accompanying drawings, in which- Fig. iv is a top view of a complete switching apparatus embodying the invention;

Figs. 2 and 3 are side and end views of the I same, respectively;

Fig. 4 is a fragmentary perspective view of the connecting device employed;

Fig. 5 is a ragmentary perspective view showing a modified type of construction, especially as to the connecting device; and

Fig. 6 is an end view of a part of the apparatus shown in Fig'. 5.

'Referring now to Figs. l, 2, and 3, the various parts are mounted on a frame of box-like conformation and constructed of angle iron. The top of this frame comprises two sections of angle iron I and l, which are rigidly secured in spaced relation by angle iron cross members 5 and t. The latter may be secured to members I and 2 by welding, or by means of screws, as shown in Fig. l. The bottom part o the frame is similar to the top and comprises sections of angle iron 3 and 4, secured in spaced relation by angle iron cross members 'I and 8. The top and bottom portions of the frame are secured together in spaced relation by vertical angle iron sections I0 and. I2 at one end, seen clearly in Fig. 3, and by similar vertical angle iron sections 9 and I I at the other end. The frame thus con all sides and at the ends and is strong and rigid'.

This frame constitutes a support for groups of structed is open on (Cl. P19-27.54)

horizontal conductors and groups ofintersecting vertical conductors, together with the associated connecting devices. The arrangement of the horizontal conductors will first be explained.

There are sets of horizontal conductors on the frame, each set comprising three conductors, and the 100 sets are divided into ten' groups of ten sets each. There are therefore thirty conductors in each group, or three hundred altogether. As a matter of fact, the drawings show two extra or-spare conductors Vin each group, making altogether 320 conductors. In each set two of the conductors are line o'r talking conductors, while the third conductor is thetes'tconductor.

The groups of horizontal conductors are supported on cross members located at the opposite ends of the frame, as may be explained for convenience in connection' with the rst'or t'opmost group. As stated, there are thirty-two conductors in the rst group, of which I5 and I6 are extra conductors. Conductors I1, I8 and I9 constitute the first set, and conductors 2|, 22, and 2t the tenth or Vlast set ofthe group. These conductors are stretched-between-two insulating 'cross members or supportate and 56, both of which can be seen in Figs. 1 and 2. The cross member 55 appears in the end view, Fig. 3, which also indicates how it is@ attached to the vertical frame members iii and i2. The construction at the other end is the same. The conductors may be of bare bronze wire or rod or of other suitable material and pass through holes drilled in the cross members and to which they are secured in any suitable ma: rer.

The other groups ci horizontal conductors are supporteclon the iframe in the same way as the first group, as can be seen clearly trom Fig. 3. The drawings show eight other cross members similar to cross member te, all attached to ver tical angle iron members i?, and each supporting a group oi thlrtyntwo horizontal conductors. There is an additional cross member similar to 55 which has been removed; that is, the drawings have been cut away at the point where it is located, .in order lto expose parts in the rear. The conductors oi the lower group are shown, however.

The vertical conductors mounted on the frame are also arranged in groups and the number of conductors in each group corresponds to the number or conductors in "each rhorizontal group, insofar as the ten sets are concerned. There are, however, three extra vertical conductors instead o two. The number of groups may or may not be the same, as will be explained subsequently in describing a typical system in which the switching apparatus may be used.

Considering the first group o! vertical conductors, counting from the righi; in Figs.'1 and 2, there are thirty-three conductors, of which 40, 4l, and 42 are extra conductors. The first .set comprises conductors 43, 44, and 45, and the tenth or last set in the group comprises conductors 5i, 52, and 53. These conductors comprise ten sets of three conductors each, and three additional conductors. All the conductors are stretched between a support or cross member above, which is attached to angle iron sections l and 2 as shown in Fig. 1, and a corresponding cross member 16 below, which is attached to angle iron sections 3 and 4.

As indicated in Figs. 1 and 2, there are a plurality of additional groups of vertical conductors, which are supported on the frame in the same way as the first group described. Fig. 1 shows four additional groups, and Fig. 2, being on a somewhat smaller scale, shows nfive additional groups, Both these drawings are broken between the ends, from which it will be understood that there are additional groups, notVJ shown.

The conductors of each vertical group pass close adjacent to the conductors of each horizontal group, but do not make contact with them. In order to keep the vertical and horizontal conductors accurately in position, a slotted bar of insulating material is provided at each intersection. These bars are shown in Fig. 2, where one of them is indicated by the reference character 24.- The bar 24 is also partly shown in Fig. ,1. Two similar bars 25 and 26 appear in Fig. 3. Each bar has an individual slot for each horizontal and vertical Aconductor at the intersection where it is located, and the conductors are therefore retained in accurate spaced relation.

At each intersection there is provided a connecting device which is adapted to connect the horizontal conductors at the intersection with the corresponding vertical conductors. The number of connecting devices is equal to the product of the number of groups of horizontal conductors and the number of groups of vertical conductors. In the example shown in the drawings there are ten groups of horizontal conductors, and if the same number of groups of vertical conductors are provided, there will be one hundred connecting devices.

Four of the connecting devices associated with the rst or upper group of horizontal conductors are shown, or partly shown, in Fig, 1. Considering the one at the left, it comprises a rectangular bar 21, which is made somewhat wider at 28 to :form an armature. This bar is suspended between pivots 29 and 30, which are adjustably mounted on two vertical metal strips 3l and 32. The construction is also shown in Fig. 3, reference being made to -bar 21', suspended between pivots 29 and 30', which are carried on the vertical strips 3I' and 32'. The latter, as well as strips 3l and 32 and other similar strips, are secured to angle iron sections I and 2 above and angle iron sections 3 and 4 below by means of machine screws, as indicated in Figs. 2 and 3.

Each bar, such as 21 and 21' just described, is operated, or rotated on its pivots, by means of an individual operating magnet. In the case of bar 21, Fig. 1, this magnet includes the core 31, winding 36, pole piece 39, and heel piece 38. Correspending parts are formed in Fig. 3, which will aid in explaining how the magnet assembly' is mounted. The core of the magnet is secured to the heel piece 38' by means of screw 35, and the heel piece in turn is secured to the vertical strip 3i by means of two smallerscrews 3l and 34. All the operating magnets are mounted in the same way, as indicated throughout the drawings.

Each bar, such as 21 or 21', carries a plurality of contact elements, as indicated in Figs, 1 and 2. Reference may also be made at this time to Fig. 4, which shows the parts in perspective and on a larger scale. The bar 21 is made slightly wider at the end adjacent the armature 28, as can be seen in the case of the bar 21' in Fig. 3, thus forming a shoulder. A rectangular metal washer 10 rests against this shoulder. The narrower portion of the bar is covered by a rectangular insulating sleeve 60, Fig. 4, on which are mounted the contact devices, such as il-GZ, separated by rectangular insulators, such as 12, 13, etc. More in detail, a rectangular insulator 1l is placed on sleeve 60 next to the washer 10, then comes the contact device 6I-62, followed by insulator 12, another contact device, another insulator 13, etc. The assembly may be secured in place by a metal washer such as 15', Fig. 3, and a wedge such as 16', the latter passing through a slot in the bar.

Each contact device, such as GI-GZ, may be made of two identical metal stampings, each having a base portion conforming to the dimensions of the washers such as 1l, with an opening punched therein conforming in size to the sleeve 60. The base portion of each stamping has an arm such as 6i and also an arm such as 62, formed integrally therewith. Two of these stampings assembled together form a contact device, adapted to connect a horizontal wire with a vertical wire, as can be seen clearly from Fig. 4. As shown in the case of the contact device 63-64, for instance, the arms 63 are in engagement with the vertical conductor 43', one on each side of said conductor, and the arms 64 are adapted to engage horizontal conductor l1 when the bar 21 is rotated on its pivots by energization of magnet 3S.

It may be mentioned here that the arms 63 are bent slightly to one side, as shown more clearly in Fig. 1, and are tensioned toward each other so that they make hrm contact with conductor 43. Arms 64 extend at right angles to bar 21 above the associated horizontal conductor l1. Each arm 64 has its tip bent into a curved configuration, the two tips of the pair being bent in opposite directions, thus forming jaws which facilitate engagement with the horizontal conductor.

The odd and even numbered horizontal conductors are in different planes, bringing adjacent pairs of jaws also in different planes, and making it possible to give each jaw a considerable curvature without danger of contacting an adjacent jaw.

Means Imay be provided to keep each pair of arms such as B4 in accurate alignment with the associated horizontal conductor such as l1. This means comprises, in the case of the pair of arms mentioned, a stud set in an opening in bar 24 and having a thin blade 8l which extends upward between the arms 64. 'I'he latter are tensioned in opposite directions against the blade BI.

It will be seen from the foregoing that each connecting device carries a plurality of contact devices, all of which are simultaneously operated by rotation of the bar on which they are mounted, and that these connecting devices are effective to simultaneously connect all the horizontal conductors at the intersection with the corresponding vertical conductors. In the example shown, there are thirty-two horizontal conductors in each group, and consequently each connecting device when operated establishes thirty-two connections.

At this point it will be convenient to describe briefly a variation from the otherwise uniform construction. The horizontal conductor which corresponds to the vertical conductors, such as 40 and I0 of the several vertical groups, is omitted and in place thereof there are provided a plurality of short rigid pins such as I4, Fig. 4, there being one of these pins at each point where the upper horizontal group intersects aA vertical group. The other horizontal groups are arranged the same way, as indicated by the showing of pin I4' in the next group down, Fig. 4. These pins are set tightly in holes drilled in the insulating bars such as 24, in the positions that would ordinarily be occupied by horizontal conductors, and cooperate with the contact devices of the connecting devices in the same manner as the horizontal conductors. Thus the contact device 6|-f62, Fig. 4,-is adapted to connect the pin I4 with the vertical conductor d.

This substantially completes the description of the switching apparatus shown in Figs. 1, 2, 3, and 4. It will be understood that the views are not necessarily all complete, as each view is intended to show only the principal features which are visible from the direction in which the View is taken. As to Fig. 2, for example, parts of the operating magnets such as 36 on the back side of the unit are visible in the actual switching unit but are not shown in the drawing. lin Fig. 3, the ends of the contact devices, which can be seen in the physical apparatus between the cross members such as 35, are not shown. They could' not be shown accurately, in fact, in view of the scale of the drawings. These omissions render the drawings clearer, on the whole,- and every part is shown in enough of the views so that the construction can be readily understood.

The arrangement and construction of the parts has been described in considerable detail, but it will be understood that this has been done merely for convenience in explaining the principles involved and by way of giving one practical example of how the invention can be carried out. A wide variation in structural details is possible within the scope of the invention.

The complete switching unit described can be used to advantage in many known automatic switching systems. One such system that may be cited a an example is the 1GO-line relay automatic telephone system which is described on pages 308 to 333, inclusive, vol. III, of Telephone theory and practice, by Kempster B. Miller. Circuits of this system are vshown on pages 320 and 321.

In a. system of the foregoing type connections between calling and called subscribers lines are established by means of link circuits or trunks, there being a suilicient number of such link circuits to handle the maximum number of simultaneous calls. Each link circuit is provided with relays at one end 'for connecting with a calling line and with similar relays at the other end for connecting with the called line.

Considerir the relays at the calling end a little more in detail, there are ten so-called tens relays, each of which is adapted to connect a particular group of ten subscribers lines to a group of ten intermediate trunks. These trunks are multiplied to all the tens relays. There are also provided ten so-called units relays, one for each of the intermediate trunks and each adapted to connect its associated intermediate trunk to the conductors of the link circuit. The link circuit ls multipled to each of the units relays.

When a subscriber makes a call, he energizes the proper tens relay of an idle link circuit to connect the group of ten lines of which his line is one to the ten intermediate trunks of such link circuit; and also the proper units relay to connect the particular intermediate trunk with which his line is connected (by the energized tens relay) to the conductors of the link circuit. These relays are energized automatically over circuits controlled bythe subscribers line relay. The operation at the called end of the link circuit is similar, except that the required tens and units relays are energized responsive to dialling the tens and units digits oi the called member.

It may be stated now that the switching apparatus unit described herein may be used to replace the tens relays in a plurality of link circuits of the relay system briefly described above. When so used the subscribers lines are connected to the horizontal conductors and the intermediate trunks to the vertical conductors. The iirst ten subscribers lines may be connected to the upper group of horizontal conductors, that is, to

the ten sets of conductors in thisvgroup; the second ten subscribers lines may be connected to the ten sets of horizontal conductors of the next group down; and so on. The intermediate trunks of the first link circuit may be connected to the ten sets of vertical conductors oi" the iirst group at the left in Fig. 2, the intermediate trunks oi vthe second link circuit tothe ten sets of vertical conductors of the next group, and so on. There may be, therefore, as many groups of vertical conductors as there are link circuits. In each link circuit the usual units relays are, oi course, provided for the purpose of connecting any intermediate trunk 'to the link circuit. The usual tens relays are omitted in each link circuit and the ten operating magnets of the ten connecting devices associated with the vertical conduc'tors assigned to the link circuit are connected in place oi such tens relays.

it will be convenient at this point to explain briefly the holding circuits for the operating magnets. Considering the operating magnet 36 and the second link circuit in which this magnet is included, the vertical conductor 4d is used as a holding conductor and is common to all the operating magnets in the same vertical row with magnet 3S. The pin i4 is individual to magnet 36 and is connected to one terminal of the niag net, the terminal to which the operating conductcr is also connected. Each of the other op.

erating magnets of this vertical row is connected in the same way to its individual associated pin such as id, whereby any magnet which is energized is enabled to connect itself to the common holding conductor d0. circuits has a holding conductor such as 4B or 46',

and the holding circuits of the operating magnets y are the same as described.

1f it be assumed now that a subscriber in the first group of ten lines makes a call, and assuming further that the second link circuit is the first idle link circuit, the initiation of the call will result in the energization of the magnet 36, which operates its associated connecting device and connects all ten of the subscribers lines Each of the other link of the rst group to the ten intermediate trunks, respectively, of the second link circuit. At the same time, one of the units relays is energized and connects the intermediate trunk in use (the one to which the calling line is connected), through to the link circuit. Relays in the link circuit are then energized over the calling line, with the result that holding circuits are completed for the energized units relay and the energized operating magnet 36, the latter circuit including the vertical conductor 40' and the pin Ill. Further details involved in the establishdevices. see Fig. 2, will be operated. These may each be associated with'a diilerent horizontal group, if one line in each group is calling, or they may all be associated with the same horizontal group, as in the case where all the calling lines are in the same group. v

It mayalso be pointed out that the continuous horizontal conductors extending past all the link circuit intermediate trunks eliminate the multiple conductors and soldered connections over which the lines are multipled to the tens relay of the dierent link circuits in the usual relay system, while the continuous vertical conductors, constituting the intermediate trunks of each link circuit, eliminate the multiple.l conductors and soldered connections between the tens relays of each link circuit. y

A switching apparatus unit similar to the one described may be used at the called end of the link circuits to replace the tens relays ordinarily used to connect with called lines. However, since the subscribers lines must have an appearance at both ends of the link circuits, the unit may be made large enough to accommodate the connecting devices for completing connections to such lines as called lines as well as the connecting devices for connecting with the lines when calling. 'I'his means, in a 1D0-line system, that two vertical rows oi' connecting devices are assigned to each link circuit.

The modification of the invention which is disclosed in Figs. 5 and 6 may now be briefly explained. This modiilcation diers from the switching apparatus unit already described in employing ilat strips or bars for the horizontal and vertical conductors instead of wires or rods, and in employing a somewhat dlilferent form of connecting device.

Fig. 5 shows parts of four conductors IDI-I of a horizontal group of conductors, parts of four conductors IUS-|08 of the next horizontal group below, and parts of four conductors IIB-I I3 of a group of vertical conductors. The drawing also shows parts of two connecting devices comprising the rotatable bars |26 and |21, the former having contact members, such as ||5 and H6, and the latter similar contact members, such as |20 and |2|.

The conductors shown are located at the front ofthe unit, or on the side opposite the operating magnets, as will be appreciated from the fact that the ends of bars |26 and |21 opposite the l drawings.

armature ends are shown. The conductors are maintained in proper spaced relation by means 'of slotted members such as |09, one of which is located at each intersection.

The connecting devices are similar to those already described, except that each contact member is a single stamping shaped as shown in the The contact members of each connecting device are assembled on the associated rotatable bar such as |21 at spaced intervals and are insulated from it and from each other in the manner already explained.

The operation of the modiiled form of connecting device will be readily understood. Bar |26 is shown in normal position, and in this position the contact members, such as I5 and IIS, have their tips in engagement with the vertical bars ||0 and as seen more clearly in Fig. 6, but they do not touch the horizontal bars I 05 and |0`6. 'I'he manner in which the contact members engage the horizontal bars is illustrated in the case of the upper connecting device, the bar |21 of which is shown in rotated or operated position. It will be seen that when bar |21 is rotated the angularly disposed tips of the contact members, such as |2l and |2| (see Fig. 6), move downward and engage the horizontal bars, such as NI and |02. Further rotation of the bar brings the entire tip portion oi each contact member between the adjacent vertical and horizontal bars, which are engaged with a sliding action, insuring a good electrical contact. The contact members are made oi' springy resilient material and are slightly warped out of position when operated, as seen in Fig. 6.

The modified form of connecting device has certain advantages from the standpoint oi' simplicity and cost of manufacture.

The invention having been described, that which is believed to be new and for which the protection of Letters Patent is desired will be pointed out in the appended claims.

I claim:

1. In a switching device, a plurality of groups of straight parallel conductors, the conductors of the several groups being arranged in parallel planes, a second plurality of groups of straight parallel conductors arranged in parallel planes which intersect the planes oi' the groups of the first plurality, means comprising a ilxed bar at each intersection to prevent movement oi the two groups of conductors at such intersection, a rigid rotatable bar adjacent each intersection and extending parallel thereto, individual means for rotating each rotatable bar about an axis which extends longitudinally of the bar and parallel to the associated intersection, and a plurality of flexible contact members carried on each bar and responsive to rotation thereof to connect the conductors of one'group at the associated intersection with the conductors oi' the other group at such intersection.

2. In a switching device, a plurality of line bars divided into groups, the bars oi' the several groups being arranged in parallel planes, and each group comprising a plurality of sets of said line bars, a like plurality oi.' sets of trunk bars arranged in a plane intersecting the planes of the said groups of line bars, a plurality of connecting bars individual to said groups of line bars, respectively, and located adjacent and parallel to the intersections of said planes, means supporting each connecting bar for rotation about an axis which is parallel to the associated intersection, means for rotating each connecting bar on its said axis independent of the 'other connecting bars, and means carried on each connecting bar responsive to rotation thereof on its said axis to connect all of the sets of trunk bars to the sets of line bars of the group of line bars which is associated with.

the rotated connecting bar.

3. In a switching device, two rows of conductors located in two intersecting planes, the conductors of one row crossing the conductors of the other row at. the intersection of said planes, respectively, a connecting device including a rotatable bar extending parallel to the line of intersection of said planes, means supporting said bar for rotation on its longitudinal axis, and a plurality of contact devices mounted on said bar, each adapted to move the same distance as the other devices and connect a conductor of one row with a conductor of the other row responsive to rotation of said bar.

4. A switching device as claimed in claim 3, in which the conductors are bare, and each contact device includes a part in continuous sliding engagement with one conductor and another part adapted to engage another conductor with a wiping action.

5. In a switching device, two rows of conductors located in two intersecting planes, respectively, means located adjacent the intersection of said planes for connecting the conductors of one row, respectively, with the conductors of the other row, and an angle member of insulating material extending parallel to the line of intersection of said planes, said member having slots at one edge for receiving the conductors of one row and slots at the other edge for receiving the conductors of the other row.

6. In a switching device, two rows of conductors located in two intersecting planes, respectively, the conductors of one row crossing the conductors of the other row at the intersection oi' said planes, means at the intersection of said planes for supporting said conductors in fixed relation to each other, a plurality of separately insulated connecting devices each adapted to connect a conductor of one row with a conductor of the other row, and means for supporting said devices for simultaneous rotation through equal distances about an axis which extends parallel to the line of intersection of said planes.

'1. In a switching device, two rows of conductors located in two intersecting planes, respectively, the conductors of one row being close to but out of contact with the conductors of the other row at the line of intersection, connecting means comprising contact devices adapted to be moved across said line of intersection and into the spaces between crossing conductors with a wedging action, and means for maintaining the conductors of one row in fixed relation to the conductors of the other row when said connecting means is operated.

8. In a switchingA device, two rows of bare conductors located in two intersecting planes, re

spectively, a connecting'device including a rotatable bar extending parallel to the line of intersection of said planes, and a plurality of contact devices mounted on said bar, each Contact device including two pairs of jaws, one of which is at all times in engagement with a conductor of one row and the other of which is adapted to engage the 1 corresponding conductor of the other row responn sive to -rotation of said bar.

9. In a switching device, two rows of conductors located in two intersecting planes, respectively, said conductors comprising rigid nat metal strips, a connecting device including a rotatable bar extending parallel to the line of intersection of said planes, and a plurality ofcontact devices mounted on said bar, each contact device comprising a iiat metal stamping having an angularly disposed end portion adapted to'be wedged between two crossing strips responsive to rotation of said bar.

10. In a switching device, a row of conductors, a plurality of other rows of conductors located in spaced parallel planes which intersect the plane of said` iirst row, said rst row including conductors which are continuous through all the other rows and at least one conductor which is discontinuous and comprises insulated sections individual to the other rows, respectively, and a connecting device at each intersection adapted to connect the conductors of the first row, including a section of said discontinuous conductor, with the corresponding conductors of the other row at such intersection.

1l. In a switching device, a plurality of rows of conductors located in spaced parallel planes, a second plurality of rows of conductors located in spaced parallel planes `which intersect the lplanes of said-first mentioned rows, each row of said second plurality including an extra conductor, and each row of said rst plurality including conductors individual, respectively, to the extra conductors of the rows of the second plurality, and a connecting device at each intersection adapted to connect all the conductors of one row at such intersection with the corresponding conductors of the other row at such intersection.

12. In a. switching device, two rows of conductors located in two intersecting planes, respectively, and extending through the intersection of said planes, abar extending parallel to the line of intersection of said planes, means for rotating said bar/on its longitudinal axis, and a plurality of spaced spring contact ngers projecting at right angles from said bar and adapted to connect the conductors of one row, respectively, to the conductors o the other row upon the rotation of said bar.

HANS P. BOSWAU.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2550242 *Mar 10, 1948Apr 24, 1951Automatic Elect LabMultiple contact, or gang, type relay
US5456608 *Aug 25, 1993Oct 10, 1995Conx CorporationCross-connect system
US5812934 *Jan 25, 1996Sep 22, 1998Con-X CorporationMethod and apparatus for a cross-connect system with automatic facility information transference to a remote location
US6031349 *Mar 20, 1995Feb 29, 2000Con-X CorporationCross-connect method and apparatus
US6265842Jun 9, 1999Jul 24, 2001Con-X CorporationCross-connect method and apparatus
DE974842C *Sep 23, 1954May 10, 1961Standard Elektrik Lorenz AgWaehlschalter fuer Fernmelde-, insbesondere Fernsprechanlagen
Classifications
U.S. Classification335/112, 335/134, 200/175, 335/127
International ClassificationH01H67/00, H01H67/26
Cooperative ClassificationH01H67/26
European ClassificationH01H67/26