US2396797A

US2396797A - Trouble lockout arrangement

Info

Publication number: US2396797A
Application number: US550096A
Authority: US
Inventors: Hugh D Macpherson
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1944-08-18
Filing date: 1944-08-18
Publication date: 1946-03-19
Anticipated expiration: 1963-03-19

Description

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March 1946- H. D. M PHERSON I TROUBLE LOCK-OUT ARRANGEMENT Filed Aug. 18, 1944 INVENTOR By H0. MAC PHERSON ATTORNEY March 19, 1946. MacPHERSON 2,396,797 TROUBLE LOCK OUT ARRANGEMENT Filed Au 18, 1944 2 Sheets-Sheet 2 SEA/DER INTEfiMED/A TE INVENTOR h. 0. MAC PHERSO/V ATTORNEY Patented Mar. 19, 1946 UNITED STTES 'ATENT OFFICE TROUBLE LOCKOUT ARRANGEMENT York Application August 18, 1944, Serial No. 550,096

8 Claims.

This invention relates to automatic telephone systems and has for its object to facilitate the removal of trouble conditions in such systems.

In many automatic telephone systems the operation of the automatic switches in the establishment of a connection is performed under the control of common control equipment, called senders, markers, etc. Such common control equipment normally completes its functions with any one call in a short time and is then released for use with a'subsequent 'call. To guard against troubles which might prevent the release of the control equipment and the switches with which it has been associated, each control circuit is provided with timing means which is started when the control circuit is seized and restored to normal when the control circuit is released. Such timing means is arranged, on completing its operation, to sound an alarm so that the maintenance force maybe informed that a trouble condition exists.

I-Ieretofore such timing means has also been arranged to automatically release the associated control circuit or, by means of an operated key or plug and jack arrangement, to lock the control circuit and the associated switches.

In accordance with the present invention, means is provided, associated with a group of similar control circuits, for causing the first timing means, which completes its operation, to always lock'the associated control circuit and also to prevent any other timing means from locking its control circuit while the first one remains locked.

To this end each control circuit is provided with two relays, a time-out relay, operated when the timing means completes its operation, and an auxiliary relay under the control of the timeout relay which are interconnected by a chain circuit including in series a contact on each auxiliary relay. Therefore,'the first operation of one auxiliary relay opens the circuit for operating any other auxiliary relay.

This auxiliary relay supplies ground to hold the control circuit busy and to prevent the release of the link by which the control circuit is connected to the trunk circuit over which the call originated.

In addition 'thefirst auxiliary relay, when oper ated, provides a circuit whereby the operation of any other time-out relay causes the immediate release of the associated control circuit and the transmission of a reorder trunk.

These "and other signal to the calling features of the invention will be made apparentby a consideration of the following description read in connection with the drawings in which Fig. 1 shows portions of a trunk circuit-and a diagrammatic link circuit and Fig. 2 shows portions of a plurality of sender circuits.

In the present disclosure, the invention has been illustrated as applied to outgoing .senders in a cross bar telephone system, but it is equally applicable to any other type of control circuit or to any other telephone system employing control circuits. For an understanding of the relative position of an outgoing sender in a telephone system and for a disclosure of the complete details of such a sender, reference may be made to United States Patent 2,293,191, granted to A. .J. Busch and F. J. Scudder on August 18, 1942.

Briefly, the outgoing sender, .to which the present invention has been applied,.is employed in a cross bar toll office. A call comes into the oflice over an incoming toll trunk, which is connected to an incoming sender or an operators position and sender according to the nature of the originating office. The designation of the wanted line is recorded in the incoming sender or operators sender and a marker controls a set ofcross bar switches to connect the incoming trunk to an outgoing trunk. In the case of most calls to be completed at a 'local oflice, the services of an outgoing sender are required and the outgoing trunk is arranged to connect with such a sender by means of a link circuit. ,The numerical designation of the called line is then transmitted by the incomingsender to the outgoing sender and the latter controls the completion of the connection to the called line.

Referring to the drawings, the outgoing trunk of Fig. 1 providesa talking connection by means of the hybrid coil i051, between the four incoming conductors It! to 104 and the two outgoing conductors H15 and H16. When the outgoing trunk was selected by themarker, a start circuit was completed for the sender link which operated to connect the trunk of Fig.1 to .the-outgoingsender of Fig. 2. The control circuit of the sender link grounds conductor l5l to operate the hold magnets of the link and also to operate start relay 26B. Relay 200 closes acircuit connecting the splitting relays of the trunk and sender which may be traced from battery through the winding of relay m1, normal contacts of relay [-08, conductor H39, front contact of relay 200, through equipment not shown to the winding of relay 201, resistance 202 and ground. Relay 20,! operates but relay It! cannot operate due to the resistance included in the circuit. Relay 20! looks to its operating circuit independent of the equipment not shown and closes a locking circuit for relay 200, and a holding circuit for the link hold magnets in place of the ground supplied by the control circuit which new releases. Relay 20| also operates off normal relay 203, which in turn closes a circuit from battery through the winding of relay 204, front contact of relay 203 to ground at the back contact of relay 205. Relay 204 also connects ground to the locking circuit of relay 200.

As indicated in Fig. 1, with relay I01 normal, direct ground, ground through a resistance or battery through a resistance is connected to conductors III and H2 in different combinations to transmit an indication to the sender of the class of the trunk. When this indication has been received, relay 205 is operatedthereby short-circuiting the right winding of relay 20| and resistance 202 and permitting relay I01 to operate. Relay I01, on operating, disconnects incoming conductors and I02, from the hybrid coil I00 and connects them to conductors III and H2, and also disconnects outgoing conductors I and I05 fromthe hybrid coil. Conductors I05 and I06 are directly connected to the sender link and bythe link to the sender. Relay I01 also opens .the circuit extending to the simplex circuit over conductors I03 and I04, which is under the control of the'terminating ofiice, to prevent the premature closure of this circuit.

The numerical designation of the wanted line is transmitted in code over conductors |0| and I 02, and conductors I I and I I2 to conductors 22| and 222 of the sender and thence to registers, not shown, where it is recorded.

When all of the digits have been recorded, relay 22:! operates, in turn operating relay 224 which connects both conductors III and M2 to battery through a. high resistance as a signal to the incoming'sender'thatit may release. The outgoing sender then either retransmits the designation over conductors I05 and I06 to the terminating office or uses the record to control automatic equipment over these conductors. When the sender of Fig. 2 has completed its functions, relay 200 is released, in

turn releasing relays

20I, 203, 204, 200 and I01. Relay I 01on releasing again connects the incoming and outgoing conductors to the hybrid coil and prepares the circuit over conductors I03 and I04 for indicating response by the wanted subscriber.

Theoperation of the sender in case of trouble will now be described.

Whenrelay 200 operated, following the seizure of the sender, it connected ground to conductor 201 supplying a general off-normal ground to various circuits of the sender. Ground on conductor 201 extends to the timing circuit 208. This circuit has been represented as a single contact but actually may comprise a plurality of relays which interact to measure a number of time intervals and close a number of control circuits. sender operates properly none of these control circuits become efiective and the release of relay 200 with the release of the sender restores the timing circuit 208 to normal. I

If, however, the sender fails to complete its functions within a predetermined time, contact 209 of the timing circuit 208 will be closed, and a circuit completed from grounded conductor 201, over contact 209, normal contacts and winding of time-out relay 2 I 0 to battery. Relay 2 I 0 operates and locks to ground on conductor 201. For the purpose ofthe lockout arrangement,

If the forming the subject of the present invention, all of the outgoing senders included in the same group with the sender of Fig. 2 are regarded as arranged in a predetermined order and contacts of the time-out relays such as relay 2! and the auxiliary relays such as relay 2|| are wired through all of the. senders in accordance with that order. To give a clearer indication'of this wiring the relays similar to relays 2|0, 2| I and 2|4 of the first, second, last and next to last senders have been indicated in the dotted rectangles at the left of Fig. 2, the sender forming the major part of Fig. 2 representing any one of the intermediate senders.

Therefore, when relay 2I0 operates, it closes a circuit from battery through the winding of auxiliary relay 2, contact of relay 200, back contact of relay 2I2 or of relay 2|3, front contact of relay 2|0, back contact of relay 2| 4, back contacts of relays similar to relays 2|0 and 2 in each of the later intermediate senders, back contacts of relays 2|0Y and 2|4Y in the next to the last sender, back contactsof relays 2 I02 and 2|4Z in the last sender and then over the normal contacts of the auxiliary relays 2| I Z, 2| IY, 2| I, and of corresponding relays inintermediate senders to the normal contacts of relay 2| IB in the second sender, normal contacts of relay 2| IA in the first sender and ground.

Relay 2| I operates in this circuit, opening at its inner right normal contacts the chain circuit above traced, thereby preventing the operation of any other auxiliary relay. Relay 2 II also looks over a circuit from battery, through its winding, contact of relay 2'00, inner right alternate con tacts of relay 2| I to ground over the normal contacts of the auxiliary relays in allof the prior senders in the chain.

Relay 2| I in operating closes a holding circuit for relay 203 which may be traced from battery through the winding of relay 203, front contact of relay 203, back contact of relay 205, back contact of relay 2|4, front contact of relay 2 to ground. With relay 203 locked, relay 204 is held operated and maintains ground on the locking circuit of relay 200 and on conductor |5| to hold the link circuit hold magnets operated and prevent the release of the sender and link from the trunk.

relay 2) is operated prior to the operation of relay223, relay 2|0closes circuits (not shown) which cause thetemporary operation and release of relay 225. .During, thetime that relay 225 is operated acircuitiselosed from grounded conductor. 201, back contactof relay 223, front conlocks under the control ofv relay 204 in the sender,

disconnects relay 191 from conductor H39 and connects it to conductor 15!, so that relay It! remains operated under the control of the sender link holding circuit, but relay 2DI of the sender releases. Relay I68 also connects interrupted ground from interrupter H3 to the simplex signaling circuit over conductors Hi3 and H14 thereby transmitting a reorder signal to the originating operator.

It is therefore apparent that, when the first of a group of senders times out, the sender with its associated link and trunk circuit are prevented from releasing, to enable the maintenance force to determine whether the trouble was in the sender, in the trunk or in the link and to remove the faulty equipment from service.

In the foregoing description, when relay 2H operated, ground was connected to conductor 215 which is connected in multiple to all of the senders of the group. Assuming that conductor 215 was grounded by some other sender, for example the first sender of the group, if the time-out relay 2l0, of the sender shown, operates during thehandling of a call the auxiliary relay 25 I cannot operate, since the chain circuit was opened by relay 2| lAof the first sender but a circuit will be completed which may be traced from ground on conductor 2l5, back contact of relay 2 Hi, back contact of relay 2i 3 or relay 2l2, front contact of relay 2), back contact of relay 2!! to the normal contacts and winding of relay 256 and battery. Relay 2l5 closes a locking circuit for itself from battery through its winding and alternate .contacts, back contact of relay 2, to grounded conductor .201. Relay 2H6 also closes a temporary holding circuit from battery through the winding and front contact of relay 203, back contact of relay 205, back contact of relay 2M, alternate contacts of relay 2l5, normal contacts of relay 2!! to ground, holding the connection until relay 218 operates as described hereinafter. With relay 2H8 operated, and relay 2H unoperated, a circuit is closed from battery through the winding of relay 25, normal contacts of relay 2 H, back contact of relay 2 l 4, front contact of relay 2l6, front contact of relay 2m to ground over conductor 226. Relay 295 looks under the control of relay 20!, opens the locking circuit of relay 203, and opens the operating circuit of relay 204 thereby leaving relay 20c and the link circuit under the control of relay 20!. Relay 205 also. closes a circuit from ground on conductor 21 to conductor H0, operating relay I08 in the trunk circuit. Relay I8 opens the circuit of relay 2Ul and permits the sender and link to release. It also transmits a reorder signal to the originating operator who releases the incoming trunk, in turn releasing the outgoing trunk and relays I01 and IE8,

When relay 2 I operates, it closes a circuit from battery through resistance 2l1, winding of relay 2"], front contact of relay 2m to grounded conductor 201, but relay 2| 8 cannot operate as long as contact 209 is closed since a shunt is closed around its winding from ground over contact 209. If the reorder signal is not transmitted or the sender released promptly, ten seconds after relay 2) operated contact 289 opens and relay 218 operates, lighting lamp M9 to identify the sender which has experienced trouble and grounding alarm conductor 221.

Relay 2; connects ground from conductor 231 to the back contact of relay 2| 4, thereby providing supplementary means for grounding conductor H0 or operating relay 205, according as relay 2 or relay 1216 is operated, in order to transmit a reorder signal in case it was not successfully transmitted previously.

Relays 2l2, H3, 21 4 and 220 function inconnection with calls to be completed by an operator, who is to receive her .instruction by means of call indicator pulsing. Relay 220 is a class relay indicating that the sender is serving such a call. Relay 2l3 operates under the control of relay .220 when a connection has been extended to the terminating ofiice and relay 214 operates from relay 2| 3, provided relay 2l2 has not been operated. Therefore, relays H3 and 214 are operated during the time that the sender is waiting for the operator at the terminating oflice to connect her call indicator apparatus to the trunk. Since this time may vary according to the density of traflic, relay 2M opens the circuit for operating relay 2H, the circuit for operating relay 2%, the circuit for operating relay 205 and the holding circuit for relay 203 so that the timing circuit is ineffective to release or lock the sender during the time that it is waiting for response by the terminating operator. However, the operation of relay 214 does not prevent the operation of the auxiliary relay in some other sender, for relay 2M when operated closes a substitute link in the chain circuit.

If it is desired to cancel this unlimited wait for the terminating operator, key 228 is operated so that whenever class relay 22 .is operated, relay 2l2 will also be operated. With relay 2l2 operated, relay 2M cannot operate following the operation of relay 2-l3, but with both relays 2l2 and 2 l3 opera-ted the circuits for operating relays 2H5 and 2H are opened. However, if the timeout relay 2m operates, while relays H2 and 2l3 are operated, a circuit is closed from ground on conductor 201, front contact of relay 2m, back contact of relay 2M, front contacts of relay 213 and 2l2 to the winding of relay 265 which gives a reorder signal and releases the sender as previously'described. If the sender should fail to release, the operation of relay 2|8 connects ground over its front contact, front contact of relay 2l2, back contact of relay 2! to conductor 215 to cause other senders which time out to release.

What is claimed is:

1. In a telephone system a plurality of control circuits, each control circuit including timing means, a time-out relay under the control of said timing means and an auxiliary relay normally under the control of said time-out relay, and means for operating the auxiliary relay in one and onlyone control circuit in response to the operation of the time-out relay in said control circuit comprising a chain circuit including a normally closed contact on the auxiliary relay in each of said plurality of control circuits and a normally closed contact on the time-out relay in certain of said control circuits.

2. In a telephone system a plurality of control circuits, each control circuit including timing means, a time-out relay under the control of said timing means and an auxiliary relay normally under the control of said time-out relay, means fo operating the auxiliary relay in one and only one control circuit comprising a chain circuit including a normally closed contact on each auxiL iary relay and a normally closed contact on a plurality of time-out relays, and means under the control of said auxiliary relay to prevent the release of the associated control circuit.

3. In a telephone system a plurality of control circuits, each control circuit including timing means, a time-out relay under the control of said timing means and an auxiliary relay normally under the control of said time-out relay, means for operating the auxiliary relay in one and only one control circuit comprising a chain circuit including a normally closed contact on each auxiliary relay and a normally closed contact on a plurality of time-out relays, and means under the control of said operated auxiliary relay to prevent said time-out relay in other control circuits from operating the associated auxiliaiy relay.

4. In a telephone system a plurality of control circuits, each control circuit including timing means, a time-out relay under the control of said timing means and an auxiliary relay normally under the control of said time-out relay, means for operating the auxiliary relay in one and only one control circuit comprising a chain circuit including a normally closed contact on each auxiliary relay and a normally closed contact on a plurality of time-out relays and mean under the control of said operated auxiliary relay to render the time-out relays in the others of said control circuits efiective to release said control circuits.

5. In a telephone system a plurality of control circuits arranged in a predetermined order, each control circuit including timing means, a timeout relay under the control of said timing means and an auxiliary relay normally under the control of said time-out relay, means for operating the auxiliary relay in one and only one control circuit comprising a chain circuit including a normally closed contact on each of said auxiliary relays and a'normally closed contact on each of the time-out relays in the control circuits later in said series, and a locking circuit for said auxiliary relay including a normally closed contact on each of the auxiliary relays in. the control circuits earlier in said series.

6. In a telephone system a plurality of control circuits, each control circuit including timing means, a time-out relay under the control of said timing mean and an auxiliary relay normally under the control of said time-out relay, an automatic release relay, means for operating the auxiliary relay in one and only one control circuit comprising a chain circuit including a normally closed contacton each auxiliary relay and a normally closed contact on a plurality of time-out relays, means under the control of said operated auxiliary relay in said one control circuit to place the automatic release relay under the control of the associated time-out relay in each of the other control circuits, and means under the control of an operated automatic release relay to restore the associated control circuit to normal.

7. In a telephone system a plurality of control circuits, each control circuit including timing means, a time-out relay under the control of said timing means, an auxiliary relay and an automatic releas relay, means responsive to the first operation of a time-out relay in one of said control circuits to operate the associated auxiliary relay, means under the control of said auxiliary relay to prevent the restoration of said control circuit to normal and means also under the control of said auxiliary relay to cause the operation of other time-out relays to operate the associated automatic release relay, said automatic release relay being eifective to restore the associated control circuit to normal.

8. In a telephone system, trunk circuits, eorder signaling means in said trunk circuits, link circuits, control circuits, means responsive to the seizure of said trunk circuits for operating said link circuits to connect said trunk circuits with said control circuits, timing means, a time-out y, an auxiliary rel y and an automatic release relay in each of said control circuits, means common to said control circuits for causing said timeout relay to operate the associated auxiliary relay in one of said control circuits and to operate the associated automatic release relay in others of said control-circuits in accordance with the order in which said timing means complete their operations, and means under the control of said auxiliary relay or said automatic release relay to operate said reorder signaling means in the associated trunk circuit, said operated automatic release relay being effective to release said link circuit and said operated auxiliary relay being effective to prevent the release of said link circuit.

HUGH D. MACPHERSQN.