US2269692A

US2269692A - Alarm signaling system

Info

Publication number: US2269692A
Application number: US161743A
Authority: US
Inventors: Victor E Rosene
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1937-08-31
Filing date: 1937-08-31
Publication date: 1942-01-13
Anticipated expiration: 1959-01-13
Also published as: GB503388A; FR841775A

Description

Jan. 13, 1942.

V. E. ROSENE -ALARM SIGNALING SYSTEM 4Filed Aug. 31, 193'! 5 Sheets-Sheet l REC TIF/ER To I rRANsM/ss/0N{ /30 /3/ REGULATOR ATTORNEY Jan. 13, 1942. v. E. RosENE. 2,259,692

ALARM SIGNALING SYSTEM Filed Aug. 31, 1957 5 Sheets-Shqat 2 1i" v Fr a i i ATTORNEY 5 Sheets-'Sheet 3 y Filedy Aug. 31 ,Y 193'! m23 :mi

/NVEN To@ L/E. ROSEN/E ATT Avv/5VI Jan. 13, 1942. v. E. Rosi-:NE-

ALARM SI'GNALING SYSTEM 5 Sheets-,Sheet 4 Fiied Aug.' 31, 193'1 TNQ . ..vTwww ,Tw

Jan. 13, 1942. V, E RQSENE 2,269,692

ALARM sIGN'ALING SYSTEM Filed Aug. 3l, A1937" 5 Sheets-Shea?l 5 /NvA/rok I YE. RSENE AHORA/5k Patented Jan. 13, 1942 ALARM SIGNALING SYSTEM Victor E. Rosene, Astoria, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application August 31, 1937,' Serial No. 161,743

5 Claims.

that some of the stations are left unattended.

Though the degree of reliability which has been attained in the development of equipment located lat such unattended stations is sufficiently high to render the failure of such equipmentimprobable, the possibility of occasional failures is always present. It is desirable, in the event of failure of the equipment at an unattended repeater station, to have available some means whereby the attendant at an attended station may be readily appraised of such failure and be informed, as Well, of the particular cause of the failure and the severity of its nature.

It is the object of this invention to provide cooperating facilities at unattended and attended repeater stations along a telephone transmission line whereby information relative to the failure of equipment at an unattended station may be transmitted to an attendant 4at an attended repeater station.

This object is attained in accordance with a feature of the invention by the provision of means at an attended repeater station which functions to selectively actuate alarm signals thereat in response to equipment failures at an unattended station.

More specifically, this object is attained by the use of alarm signals at an attended repeater station which are controlled by switching equipment at an unattended station, which responds to equipment failures thereat, over a normally closed loop circuit consisting, in the case of a cable carrier telephone system, of two-line conductors and, in the case of an open wire carrier telephone system, of a single line conductor and earth. At the auxiliary or unattended station a group of relays is provided, each relay corresponding to an individual alarm condition and operating upon the occurrence of an equipment failure. At the main or attended station a corresponding group of relays is provided to operate an equal number of different lamp signals.

station, ground potential is applied to a relay inl the alarm trunk circuit which relay in turn operates to transmit a startl signal over the line circuit to the main station Where a relay interrupter is started to function and audible and visual signals are operated. The interrupter is used to operate selector switches in both the main and auxiliary stations. The selector at the auxiliary station hunts for ground on the selector contacts and upon reaching the grounded contact, a signal device associated with the corresponding contact of the selector at the main station is actuated to register thereat the occurrence of the trouble condition existing at the auxiliary station.

The invention will be readily understood from the following detailed description made with reference to the accompanying drawings in Which Figs. 2, 3, 4 and 6, when arranged in the manner indicated in Fig. l, combine to illustrate the invention as applied to a cable circuit and Figs. 2, 3, 5 and 6, when arranged in the manner indicated in Fig. l, combine to illustrate the application of the invention to an open wire circuit. The equipment shown on Figs. 2 and 3 and the upper halves of Figs. 4 and 5 are located at the unattended station whereas the equipment shown on the lower halves of Figs. 4 and 5 and on Fig. 6 is located at the attended station.

Cable circuit in Fig. 2 there is shown a miscellaneous alarm circuit which functions upon the occurrence of trouble conditions at an unattended repeater station to originate alarm signals. Applicant has elected to describe the operation of the system under but four trouble conditions, it being understood that the equipment may be elaborated upon, and in actual practice is so, to provide for the transmission of a greater number of alarm signals.

Relay l may be considered to be actuated in any well-known manner upon the failure of a piece of apparatus, such as a rectifier, at an unattended repeater station to connect ground to the winding of relay 2 which relay operates in an obvious circuit. At its armature `and front contact relay 2 causes relay 3 to operate in a circuit extending from grounded battery, winding of relay'3, front contact and armature of relay 2, conductors 4 and 5 to ground by way of the inner right-hand armature kand back cont-act of When a trouble condition occurs in the auxiliary 55 relay 6. At its outer right-hand armature relay 3 prepares an obvious circuit for lamp l which may be completed by the actuation of key 8. 'I'he lamp 1 at the auxiliary station is lighted upon the arrival of an attendant thereatand the subsequent actuation of the key 8. At its inner right-hand armature and front contact relay 3 establishes an obvious circuit for relay 9 which relay, in operating, causes relay to operate in a circuit extending from grounded battery, conductor winding of relay I0 to ground by Way of the front contact and armature of relay 9. Relay 9, however, is slow-to-operate and a period of two and one-half minutes elapses before the circuit to relay I0 is completed. The purpose of this time delay is to allow sufficient time for the trouble condition to clear itself before the alarm signal is transmitted to the main or attended station.

It will be assumed that the trouble condition (rectifier failure), does not clear itself, and relay Ill operates. At the inner left-hand armature and front contact of relay I0 a circuit for relay |2 (Fig. 3) is established which extends from grounded battery I3, conductor i4, winding of sensitive relay I2, conductor l5, high resistance I6, back contact and right-hand armature of relay |1, conductor |8, front contact and left-hand armature of relay 3 to ground by Way of the front contact and inner right-hand armature of relay I0.

Relay 2U (Fig. 4) now operates in a circuit extending from grounded battery I3, conductor |4,

conductor 2|, winding of relay 20, conductor 22, armature and front contact of relay I2 to ground on the conductor 23. At its left-hand inner armature and front contact, relay establishes a circuit for relay 24 (Fig. 3) extending from grounded battery |3, conductor |4, winding of relay 24, conductor 25, inner left-hand armature and front contact of relay 2D, conductor 26 to ground at the back contact and left-hand armature of off-normal relay 21 (Fig. 3).

The selector Se at the auxiliary station is normally in the released position when an alarm comes in and the loop circuit between stations is normally closed. This normally closed loop extends from grounded battery 29 at the main station (Fig. 4) back contact and right-hand armature of relay 30, tip windings of coils 3| and 32 at the main station, tip conductor of the line extending between stations, tip windings of coils 33 and 34 at the auxiliary station, winding of normally energized relay 35, winding of polarized relay 36, resistance 31, ring windings of coils 34 and 33 at the auxiliary station, ring conductor of the line, ring windings of coils 32 and 3| at the main station, winding of normally energized relay 3B, left-hand armature and back contact of relay 30, winding of marginal relay 39 to ground at the back contact and right-hand outer armature of relay 49. Coils 3|, 32, 33 and 34 with their associated condensers are useful in the circuit to prevent the operation of the alarm circuit from interfering with telephone communication over the same line conductors.

Relay 39 is a marginal relay and does not operate until relay 24 operates to short circuit resistance 31 which it does at its armature and front contact. Relay 42 (Fig. 6), which is normally operated in an obvious circuit now releases due to the connection of ground to the winding of relay 42 and resistance 43 by way of the armature and front contact of relay 39 over conductor 44, and thence to ground at the inner right-hand armature and back contact of relay 46. Relay 42 in releasing establishes a circuit for the start relay` 45 which may be traced from grounded battery, winding of relay 45, conductor 46, back contact and left-hand armature of relay 41, conductor 48, outer right-hand armature and back contact of relay 49, conductor 56, back contact and left-hand armature of relay 5| t0 ground at the back contact and armature of released relay 42. Relay 52 also operates as a consequence of the release of relay 42 in a circuit extending from grounded battery, right-hand winding of relay 52, conductor 53, normal right-hand contacts of key 54, conductor 55, outer right-hand armature and back contact of relay 41, back Contact and left-hand armature of relay 5| to ground at the back contact and armature of released relay 42.

Relay 52, by way of its front contact and lefthand armature locks to ground at the left-hand contacts of key 54. At its two right-hand armatures and front contacts, relay 52 establishes obvious energizing circuits for the lamp 5G and audible signal 51. The audible signal 51 may be silenced by the actuation of key 54, which opens the circuits to both windings of relay 52 causing this relay to release.

Relay 45, at its left-hand armature and back contact opens the obvious locking circuit for relay 59, which relay if operated would release to release the selector Sm, at its outer right-hand armature and front contact relay 45 establishes a circuit for relay extending from grounded battery, winding of relay 69, conductor 6|, front contact and outer right-hand armature of relay 45, conductor 62 to ground at the normal lefthand contacts of key 54.

Relay 60 by way of its inner right-hand armature and front contact locks in a circuit extending from grounded battery, winding and front contact and inner right-hand armature of relay 66, conductor 63, back contact and right-hand armature of relay 64, conductors 65 and 66 to ground at the right-hand contacts of recheck key 61.

At its left-hand armature and front contact, relay 60 applies ground to start conductor 68 which starts the relay interrupter consisting of relays 69, 1D, 1|, 12 and 13 operating.

Relay interrupter circuit Ground potential on conductor 68 operates relay 13 in an obvious circuit, which relay at its armature and back contact removes a short-circuit from the winding of relay 12 causing this relay to operate. Relay 12 in like manner removes a short-circuit from the winding of relay 1| which relay operates and at its outer armature and front Contact establishes an Obvious circuit for relay 1D. Relay 10 operates and locks directly to ground on the lead 68. Relay 69 does not operate at this time as it is short-circuited by its own back contact and armature and the outer armature and front contact of relay 1|.

When relay 1| operated, it short-circuited the winding of relay 13 by way of its front contact and inner armature. Relay 13 releases and reestablishes the short circuit about the winding of relay 12 which relay releases to reestablish the short-circuit about the winding of relay 1|. Relay 1| accordingly releases and at its outer armature and front contact removes the ground on lead 68 from the left-hand armature of relay 69 which allows relay 69 to operate to ground on the lead 68 by way of the armature and front contact of relay 10.

Relay 69, operated, connects ground to the lead 14 and at its left-hand armature transfers the lead from the outer armature of relay 1| to the resistance 'l5 and Winding .of relay '10. When relay 'H releases as described above, relays 13, 12 and l|` operate again successively. When relay 'H operates the second time, ground is connected by lway of the outer armature and front contact of relay 'il to the left-hand armature and front contact of relay 69 Which, as already mentioned, are connected to the resistance 15 and Winding of relay 10. Relay 10 accordingly releases but holds relay 69 operated. Relay 'H operated the second time causes relay 13 to release and subsequently relays 12 and 'Il release in the manner previously described. When relay 'H releases the second time, ground is also removed from relay 69 which relay releases causing the removal of ground from the lead 74.

The above operation Will be repeated over and over again to give an interrupted ground connection on lead l4 at the rate of approximately interruptions per minute, as long as ground remains connected to the start lead 68. The rst make pulse on the lead 14 will always be of the proper length because the interruptor starts with all relays released. The nal make pulse on the lead 74 may be short depending on When ground is removed from the lead 68.

The relay interrupter supplies ground on lead 'I4 at the approximate rate of 25 times per minute. The rst ground pulse operates relay 48 in an obvious circuit which relay, at its outer right-hand armature and back contact opens the loop circuit extending between

stations causing relays

39 and 38 at the main station and relay at the auxiliary station to release. Relay 39 released, permits relay .42 to reoperate. Relay 40, at its inner left-hand armature and front contact causes relay 49 to operate in an obvious circuit and its inner right-hand armature and front contact establishes an obvious circuit for relay 'll to hold this relay operated when relay 38 releases as already mentioned. Relay 49, at its outer left-hand armature and front contact causes the resistance 'I8 to be connected across the tip and ring conductors of the line on the main station side of the retard coil 3|; the inner left-hand armature and front contact of relay 49 completes this connection. The connection of resistance 18 helps to discharge the line quickly and thereby hastens the release of relay 35 at the auxiliary station. Relay 35 controls the operation of lamp' 99 in Fig. 2.

Relay 35 at the auxiliary station released, opens the normally energized circuit to relay 19 (Fig. 3) causing this relay to release and establish an obvious energizing circuit for' relay 88. Relay 80 operated, at its right and left-hand armatures opens the leads 8| and 82 to the brushes d and b of selector Sa at the auxiliary station. The opening of lead 8l to selector brush d prevents the operation of relay 88 when the selector Se steps to position No. 10. At its front contact and right-hand armature relay Si) establishes a circuit extending from grounded battery 84, selector rotary magnet 8'5, conductor 86, outer lefthand armature and front contact of relay 20 (Fig. 4), conductor 8l, back contact and righthand armature of relay 88, conductor 89,V front contact and right-hand armature of relay 89 to ground by Way of the back contact and lefthand armature of relay 99. The rotary magnet 85 operates in this circuit to step the selector Se to position No. 1. In this position, relay 21 operates in a circuit extending from grounded battery 9i, winding of relay 2l, conductor 92 to ground at the off-normal contacts 93 of the LEI) selector. The off-normal contacts 93 close when selector Se operates to position No. 1 and remain closed until the selector is released. Relay 21 at` its left-hand armature and back contact removes ground from the previously traced energizing circuit for relay 24, which relay releases.

Relay 4.9 at the main station (Fig. 6) operated, .establishes a circuit for rotary magnet v94 extending from grounded battery, Winding of rotary magnet 94, conductor 95, back contact and right-hand armature of relay 59, conductor 98 :to ground at the front contact and outer lefthand armature of operated relay 49. Rotary magnet 94 steps selector Sm to position No. 1. Relay 49 at its outer left-hand armature removes ground from the selector brush a to prevent relay 59 from operating When the selector steps to position No. 10. At its outer right-hand armature, relay 49 opens the circuit to the start relay which relay releases and at its inner lefthand armature connects, as hereinbefore mentioned, resistance 18 across the cable pair.

The relay interrupter at the main station then removes ground vfrom conductor 'i4 (hereinbefore described) which causes relay 40 to release, which, in turn, releases relay 49. right-hand armature relay 40, released, again connects ground to the loop circuit to cause relays 38 and 35 to reoperate. At its outer lefthand armature, relay 40 opens the circuit to resistance 18 to prevent marginal relay 39 from operating momentarily. Relay l1 is a slow release relay which holds operated while ground to its Winding is transferred from the inner right-hand armature and front contact of relay 49 to ground from the front contact and armature ofoperated relay 38. l

Relay 35 at the auxiliary station in reoperating completes an obvious circuit to relay 19 (Fig. 3) which relay operates and in turn, releases relay 88 to close the circuit to relay 24. Relay 24 is now connected to the brush b of selector Sa by Way of conductor 82, left-hand armature and back contact of relay and conductor 25. If ground is found on the rst contact of the selector Sa, relay 24 will operate.

Upon the occurrence of the rectifier failure at the auxiliary station as mentioned in the early part of this description, We found that ground potential at the inner left-hand armature and front contact of relay I8 (Fig. 2) Was connected to contact 3 of the selector Se at the auxiliary station by Way of the left-hand armature and front contact of relay 3, conductor l 8, right-hand Winding of relay Il (Fig. 3) and conductor |88. Ground potential is therefore not found at position No. l of the'selector Se so that the selector is advanced to position No. 2 and then to position No. 3 under control of the relay interrupter in the same manner as it was advanced to position No. l upon the rst ground pulse reaching conductor 'i4 as already described.

When the brush b of selector Se reaches contact No. 3 which is now grounded through the right-hand Winding of relay il from lead i8, relays 24 and Il both operate (it having been just described how this relay is connected to the brush b wlien relay 88 releases). Relay 24 in operating, again short circuits the resistance 31 so that marginal relay 39 (Fig- LDin the loop circuit between stations operates and connects the ground potential at the inner right-hand armature and back contact of relay 49 to the battery side of the winding of relay 42 by Way` of conductor 44 thereby causing relay 42 to release.

At its outer Reverting back to the time when selector Sm at the main station stepped to position No. 1, a circuit was established extending from grounded battery, Winding of relay 41 (Fig. 6), oil-normal contacts |8| of the selector Sm, front contact and outerright-hand armature of relay 60, conductor 63, back contact and right-hand armature of relay 64,

conductors

65 and 06, to ground at the right-hand normal contacts of recheck key 61. Relay 41 operates in this circuit and locks up on its inner right-hand armature and front contact, transferring by the operation of its left-hand armature, the lead 48, now grounded by the release of relay 42, to the brush c of the selector Sm by way of conductor |04. The circuit to the right-hand winding of relay 52 is also opened at the outer right-hand armature of relay 41.

So far there has been shown how the selectors Sa and Sm advance from one position to another until the brush of selector Sa arrives at a grounded contact. In the present description Contact 3 of this selector has been grounded so that when this contact is reached by the selector Sa a corresponding contact 3 of selector Sm is reached. Now, with relay 42 (Fig. 6) released, a circuit is established extending from grounded battery, Winding of relay |02, normal make-before-break contacts of relay |02, conductor |03, contact 3 and brush c of selector Sm, conductor |04, front contact and left-hand armature of operated relay 41, conductor 48, outer right-hand armature and back contact of relay 49, conductor 50, back contact and left-hand armature of relay to ground at the back contact and armature of relay 42. Relay |02 operates in this circuit and locks to ground at the normal contacts of recheck key 61. At its right-hand armature and front contact relay |02 establishes an obvious circuit for lamp |05. At its outer left armature and front contact, relay |02 completes an obvious circuit for lamp 55, which lamp identifies the particular trouble condition which exists at the auxiliary station. Relay |02 also opens the lead from contact No. 3 of the selector Sm to prevent a feedback circuit when the selector brush c bridges two contacts while stepping.

The interrupter continues to operate and during the rst ten pulses, causes the selectors Sa and Sm to advance over the ten contacts illustrated. When the selector Sm steps to position l0, an obvious circuit is completed to the winding of relay 59 which relay operates upon release of relay 49 which occurs after the tenth pulse of ground has been applied to and removed from the lead 14 by the relay interrupter. When ground is removed from lead 14 by the release of relay 69 after the tenth impulse of the interrupter circuit, relay 40 restores its armatures causing relay 49 to release. Relay 59, operated, locks to ground at the left-hand armature of relay 45 by way of the back contact and left-hand armature of relay 64.

Relay 59 operated, transfers the lead 98 from relay 49 which normally goes to the rotary magnet 94 of selector Sm, to the release magnet |06 of the selector Sm. Relay 59 operated, also closes a circuit from grounded battery, winding of relay |01, conductor |08, outer left-hand armature and front contact of relay 59, which circuit is completed to ground at the inner right-hand armature of relay 49 when this relay reoperates on the eleventh pulse.

In the case of the selector Se at the auxiliary station the release relay 88 (Fig. 3) operates on its primary Winding as follows: When relay 80 released` as previously described, a circuit is established extending from grounded battery |08, conductors |09 and ||0, left-hand Winding of relay 88, conductor |2, contact No. 10 of selector Sa and the brush thereof, conductor 8|, back contact and right-hand armature of relay to ground at the back contact and left-hand armature of relay 90. Relay 88 in operating, transfers the lead 89 from relay 80 which normally goes to the rotary magnet to the release magnet I3 of the selector Sa. Relay 88 locks to ground at the inner right-hand armature and front contact of operated relay 21 by way of its own inner lefthand armature and front contact.

The eleventh pulse from the interrupter causes relays 40 (Fig. 4) and 49 (Fig. 6) to operate in the hcreinbefore described manner. Relay 40 opens the loop circuit between stations, Whereupon relay 35 (Fig. 4) restores its armature which opens the circuit to relay 19 (Fig. 3), which relay thereupon releases and closes the circuit to relay 80. Relay 49 in operating completes the circuit to the release magnet |06 thereby causing the selector Sm at the main station to be returned to normal. The return of the selector to normal opens the oir-normal contacts |0| in the circuit to the winding of relay 41, but this relay remains locked up as hereinbefore described.

When relay 80 (Fig. 3) at the auxiliary station operates on the eleventh pulse, a circuit is established extending from grounded battery |20, Winding of release magnet ||3, conductor H4, front contact and outer left-hand armature of relay 88, conductor 89, front contact and righthand armature of relay 80 to ground at the back contact and left-hand armature of relay 90. A circuit was also established for the energization of the right-hand winding of relay 88 extending from grounded battery |08, conductors |09 and H0, right-hand winding of operated relay 88, front contact and right-hand armature of relay 88, front contact and right-hand armature of relay 80 to ground at the back contact and lefthand armature of relay 90.

When the eleventh pulse from the interrupter released the selector Sm at the main station, ground was supplied from relay 49 to operate relay |01 as previously described. Relay 64 cannot operate while ground is connected directly to relay |01 but will operate in series with relay I 01 as soon as relay 49 releases to remove this ground. The ground for the series operating circuit for relays |01 and B4 is found at contact |2| associated with relay 01. When relay 84 does operate, ground is removed from relays B0 and 59 causing them to release. Relay 60 released, disconnects ground from the start lead G8 to stop the interrupter and supplies ground to short circuit relay |01 causing this relay to release and in turn, release relay 64. Relay 60 released, also opens the locking circuit to relay 41, causing this relay to release.

When ground was present on lead |8 (Fig. 2) due to the trouble condition at the auxiliary sta tion, relays 24 and |1 (Fig. 3) both operated in series, as hereinbefore described. Relay |1 then locked up to ground on lead |8 by way of its front contact and left-hand winding from grounded battery 9| by Way of the back contact and right-hand armature of relay 90 (Fig. 3). Relay I1 operated, disconnects resistance I6 from ground on the lead 8 which caused relay |2 to release. Relay 20 (Fig. 4) then releases and opens the circuit to relay 24 (Fig, 3) which later releases when relay 80 releas-es and opens a parallel'circuit to relay 24.

Ground on any lead, such as I8, will operate relay 24 as already described, through the corresponding selector contact, such as contact 3, and will also lock up the -corresponding relay, such as relay |02 (Fig. 6). If an alarm comes in while the selector is stepping and is not registered on the rst cycle, this alarm will immediately cause the alarm circuit to go through its cycle a second time after the release of the selectors at both stations.

The foregoing description covers the transmission of an alarm signal from an auxiliary station to a main station upon the occurrence of a rectifier failure at the rst station. Such an occurrence causes the lead I8 to be grounded which results in the operation of relay 52 to bringin a general alarm at the main station, applies ground potential to a particular 4contact of the selector Sa at the auxiliary station, causes the start of a relay interrupter which drives the selectors Sa and Sm at the two stations substantially simultaneously until the first-mentioned selector arrives at the grounded terminal, whereupon relay |02 at the main station functions to actuate signals which identify the nature of the trouble ccndition at the auxiliary or unattended station.

In the event of a failure of equipment of another nature such as a transmission regulator with which relay |30 (Fig. 2) is associated, this relay releases in any well-known manner to cause relay I3| to operate in a circuit extending from grounded battery, winding of relay |3|, armature and back contact of relay |30, conductor 5 to ground at the inner right-hand armature and backcontact of relay B. Relay |3| in operating establishes an obvious circuit for slow-to-operate relay 9 which, when it operates, causes the operation of relay I0. At its innermost armature and front contact relay I 3| prepares a circuit yfor lamp |33 which may be completed upon the actuation of key 0 upon the arrival of an attendant at the normally unattended auxiliary station. When relay I0 operates, and assuming lead |34 corresponds to the lead I8 mentioned during the previous description of the transmission of an alarm signal upon the failure of a rectifier at the auxiliary station. 'Ihe lead |34 rpasses through the right-hand winding of relay |35 (Fig. 3) to the contact No. 4 of -the selector Sa. The operation of the system from this point on is the same as that described in connection with the grounding of contact No. 3 of the selector Sa with the exception that relay |36 (Fig. 6) operates to energize the lamp signal |31 to identify the particular nature of the trouble condition.

It will now be assumed that the source of outside power indicated at |40 fails. Under this condition relay I4I restores its armatures, the outer one thereof preparing an obvious circuit for lamp signal |42. At its inner armature and back contact, relay I4| establishes an obvious circuit for relay |43 which relay performs no function at this time.

When the power failure occurs, the rectifier and regulator alarms also function causing relays 2, 3 and I3I to operate. The slow-to-operate relay 9 is accordingly energized and when operated, causes relay I0 to operate in an obvious circuit.`

Aing the selector to release.

Relay I0 at its right-hand armature and front contact connects ground to the winding of relay l6 by way of the left-hand armature and front contact of relay |43. Relay 6 accordingly operates.

Relay 3 at its inner right-hand armature and back contact removes ground from the lead 5 which causes relays 3 and |3| to release to prevent rectifier and regulator alarms from being registered in the attended oice during a power failure. At its left-hand armature and front contact relay 6 locks up to ground on the lead |44 which terminates at the front contact and inner right-hand armature of relay |43 and also at the back contact and armature of relay |45 (Fig. 4). Relay 6 is also under control of relay I0. At its alternate make-before-break contacts, relay 6 connects ground by way of the front contact and outer right-hand armature of relay |43 to conductor |45 which corresponds to the leads I8 and |34 of previous descriptions. The lead |46 is connected to the contact No. 6 of selector Se at the auxiliary station by way of the right-hand winding of relay |41 (Fig. 3). The operation of the system from this point on is the same as previously described except that relay |48 and lamp y|49 function in a manner obvious to identify the power failure condition.

When the power is restored, relay |43 releases and ground at the front contacts and armatures of relay I4I is connected to the lead |50 by way of the outer right-hand armature and front contact of relay 6. The lead |50 corresponds to leads I8, |34 and |45 and is connected to the contact No. 7 of selector Sa. The system then functions in the manner previously described whereby relay V| 5| and lamp |52 (Fig. 6) function to register the power restoration alarm. When relay |4I reoperates, relay |43 releases and disconnects the ground on lead |46.

In the previous descriptions of the transmission of alarm signals from an unattended station to an attended station it was assumed that the loop circuit interconnecting the stations was closed as would normally be the case. If, for any reason, the loop circuit is open upon the occurrence of a trouble condition relay 35 (Fig. 4) restores its armature and the circuit to relay 19 is opened so that relay 19 is released. rRelay 80 accordingly operates to cause the selector Sa to step in a manner already described. Ground from the off-normal contact 93 will then operate `relay 21 which in turn operates relay |55 in an obvious circuit. This relay after an appreciable 'interval of time (2 to 3 minutes) closes an obvious circuit to relay which relay operates. Relay 90 atv its left-hand armature removes ground from the selector rotary magnet 05 and appliesV it to the selector release magnet I I3 caus- The selector in the released position releases relay 21 which removes 'ground from relay |55 causing this relay to release quickly and in turn release relay 90. If the loop circuit remains open, the selector will again operate which causes the reoperation of relays 21 `and I 55 to again release the selector. This action continues until the loop circuit is closed. Relay 90 operated, also releases any of the relays I1,

|35, |41 and |56 which may have have been locked up.

An open loop circuit between stations, will also cause'relay 38 (Fig. 4) to restore its armature and the circuit to relay 11 is opened so vthat relay 11 is released. Relay 42, therefore releases and Relay 52 operated, effects the operation of the lamp 56 and audible signal 51. Relay 45 operated, causes relay 60 to operate to start the interrupter. The operation of the release key 54 in this case releases relay 52 to stop the audible signal 51, opens i scribed. Relay 45 is slow-to-release and operatesv in a circuit extending from grounded battery, winding of relay 45, conductor 4S, back contact and. left-hand armature of relay 41, outer righthand armature and back contact of relay 49,

back contact and left-hand armature of relay'-A 5| to ground at the armature of released relay 42. Relay 45 operated, closes the circuit to relay 5|, which operates and opens the circuit to the winding of relay 45. Relay 45 then releases and key 54 may be released. Relay 5|-K operated, also closes a circuit at its front contact and right-hand armature to keep lamp 56 lighted. When the loop circuit between stations is restored, relays 38, 11 and 42 reoperate and relay 5| releases to restore the circuit to normal.

Recheckz'ng signals When it is desired to verify the lamp signal received from the auxiliary station the recheck key 61 (Fig. 6) may be actuated by the attendant at the main or attended station. The actuation of key 61 causes relay 30 (Fig. 4) to operate in a circuit extending from grounded battery, winding of relay 36, conductor |51 to ground at the right-hand alternate contacts of key 61. key 61 may be actuated while the selectors are stepping if so desired. Relay operated, reverses the battery polarity on the loop circuit which causes the polarized relay 36 (Fig. 4) to operate. selector Sm and removes ground from the relays I 62, |36, |48 and |5| which releases these relays and extinguishes the associated lamps |05, |31, |49, |52. Relay 38 (Fig. 4) in the loop circuit may release momentarily when relay 3|) operates but the associated relay 11 being slow-to-release will remain operated. Relay 35 (Fig. 4) and relay 19 (Fig. 3) may also release upon the operation of relay 3) but will immediately reoperate.

Relay 86 (Fig. 3) being slow-to-operate will re- 1,4

main released.

When polarized relay 35 (Fig. 4) operated, ground was supplied to cause relay to operate in an obvious circuit which relay in turn, caused relay to operate in an obvious circuit by Way of lead 29D. Relay |45 operated, also removes ground from conductor |44, which will release locked-up relay 6 (Fig. 2) when the outside power source is restored. 'Ihe power restoration alarm registered by lamp |52 (Fig. 6) cannot therefore be rechecked. Relay 90 operated, supplies ground at its left-hand armature and front Contact to the release magnet II3 of selector Se at the auxiliary station to release the selector in case it is operated and also removes ground from relays I1, |35, |41 and |56 at the auxiliary station causing them to release. The release of these relays, key 61 and relays 30, 3G, |45 and 90, causes the alarm circuit to start operating again to relight the same lamps such as |65, |31, |49, |52

The

The key 61 operated, also releases the |50 to the winding of relay I2.

Open wire circuit The alarm system as applied to open wire circuits is illustrated by Figs. 2, 3, 5 and 6 arranged in the manner shown in Fig. 1. In this case the alarm circuit between stations is operated over a single conductor with a ground return. A duplex telegraph circuit is used supplied with volt telegraph battery 263 at the main station and a 152-volt battery |3 at the auxiliary station. When the telegraph circuit is idle, the higher voltage battery at the auxiliary station is delivering current to hold a relay operated In the main station. An alarm in the auxiliary station will operate a relay to substitute ground for the higher voltage battery normally connected to the line circuit causing the release of a relay at ythe main station which operates an audible alarm and starts the relay interrupter. The selector at the auxiliary station is caused to operate by the connection of the lower voltage battery to the line circuit at the main station which causes a relay in the auxiliary station to operate and in turn step the selector. The selector in the main station is caused to operate in step With the auxiliary station selector.

The disclosures of the open wire and cable circuit arrangements Iare the same except that Fig. 5 of the former replaces Fig- 4 of the latter. It is quite apparent therefore that a major portion of the detailed description of the cable circuit arrangement just given will apply to the open Wire circuit so that it is deemed permissible in the description of the latter to resort to abbreviated circuit description Wherever possible.

In the description of the cable circuit arrangement it has been shown how the leads I8, |34, |45 and |56 become grounded to effect the transmission of alarm signals to the attended station upon the occurrence of certain conditions at the unattended station such as rectifier, regulator and power failures and power restoration. The following description will cover only the condition of rectier failure which results in the application of ground potential to Athe lead I8.

Ground on lead I8 operates relay I2 (Fig. 3) in the manner previously described and as a result, relay 220 (Fig. 5) operates in a circuit extending from grounded battery I3 (Fig. 3), conductors I4 and 2|, Winding of relay 220, conductor 22, armature and front contact of relay I2,

conductors

23, 222 and 26 -to ground at the back contact and left-hand armature of relay 21. The selector Se is normally in the released position when an alarm comes in and the line circuit between stations is normally closed with l52-volt battery I3 connected at the unattended oiflce and ground connected at the main office.

The normally closed line circuit extends from grounded battery I3 (Fig. 3), conductors I4, 2|, 22|, resistance 224, back contact and left-hand armature of relay 220, right-hand winding of polarized relay 225, left-hand winding of impedancecoil 58, line conductor interconnecting the two stations, left-hand winding of impedance coil 232, back contact and right-hand armature of relay 226 to ground by way of the right-hand winding of polarized relay 221. Relay 221 is normally operated in the idle condition of this circuit. The left-hand winding of relay 221 biases the relay in a non-operate direction. It will be noted at this time that relay 225 comprises three windings, the right-hand winding referred to as the line winding, the middle winding known as lthe network Winding Iand the left-hand winding which is a biasing winding. The right-hand and middle windings are differential with respectto each other so that current in the circuit just traced for the right-hand winding tends to release the relay but is balanced by the current in the middle winding which tends to operate the relay so that under this condition the net effect is zero. The left-hand biasing winding tends to hold the relay 225 released. Y

When relay 220 (Fig. operates, as described, ground is connected to the line circuit by way of conductor 228 and the front contact and lefthand armature of relay 22|] in place of battery I3 thereby causing relay 221 to release. The release of relay 221 removes ground from the winding of relay 42 (Fig. 6) causing this relay to release. As in the description of the cable circuit arrangement, relay 42 released, operates relays 45 and 52 the latter locking up to key 54 and effecting the operation of lamp signal 56 and audible signal 51. Relay 45 operated, releases the Iselector Sm if it is locked up and also supplies ground to relay 5|) which relay operates and locks up through the right-hand armature and back contact of relay 64 to ground at the recheck key 61.

Relay 6D operated, starts the interrupter circuit functioning from ground on the start lead 68. Relay 60 also removes ground from the rst make contact associated with the armature of relay |51 which allows this relay to operate at a later time.

The audible signal 51 may be stopped from operatng by the operation of key 54 which releases relay 52 as soon Ias the interrupter has started and caused relay 41 to operate as previously described.

The relay interrupter circuit including relays 13, 12, 1|, 15 and 65, supplies ground on lead 260 at the approximate rate of times per minute as long as the lead 68 remains grounded. The first ground pulse operates relay 49 in an obvious circuit which includes the conductor 260 shown on Fig. 5. Relay 49 operated, steps the selector Sm at the main station to position No. 1 and removes ground from the brush a to prevent relay 5S from operating when the selecto-r steps to position No. l0.

When the selector Sm stepped to position No. 1, ground from the olf-normal contacts IUI operated relay 41 which transferred the lead 43 from the relay 45 to the lead |04 to the brush c of the selector. The circuit to relay 52 also opened when relay 41 operated.

At its inner left-hand armature and fro-nt contact relay 4&1 establishes a circuit extending from grounded battery, right-hand winding of relay 226 (Fig. 5) conductor 28|, inner left-hand armature and front contact of relay 49, conducter 262V to ground. Relay 226 operates in this circuit and at its right-hand armature and front Contact establishes an obvious circuit to the right-hand winding of relay 221 and at its lefthand armature and fro-nt Contact connects the 13G-volt battery 253 to the line circuit through resistance 254 thereby causing relay 225 to operate in a circuit extending from grounded battery 263, resistance 25e, front contact and left-hand armature of relay 22B, left-hand winding of impedance coil 232, line conductor, left-hand winding of impedance coilv 55, right-hand Winding of relay 225 to ground by way of the left-hand ar'- mature and front contact of relay 222. It will be noted that the middle Winding of relay 225 is now short circuited by the left-hand armature of relay 220 so that relay 225 operates by way of its right-hand winding as just described.

Relay 221 operated, reoperates relay i2 (Fig. 6) over an obvious circuit. Relay 49 operated opens the circuit to start relay 45 which relay releases. Relay 225, operated, opens the energizing circuit for relay 19 (Fig. 3) causing this relay to release and in turn complete the circuit to relay B which relay thereupon operates. Relay operated, opens the circuits from the brushes of the selector Sa and supplies ground to operate the selector to position No. l. Relay 225 also causes the audible signal 22| to be operated (when key 240 is actuated) in a circuit extending from grounded battery 9|, conductor 242, bell 24|, right-hand contacts of key 24U (when closed) to ground at the front contact and armature of relay 225. When key 240 is operated the lamp 243 is lighted as a guard signal.

`With the selector` in position No. 1, relay 21 operates to remove ground from relay 220 (Fig. 5) causing this relay to release which transfers the right-hand and middle windings of relay 225 from ground to battery I2. Current now ows in the middle winding in the operate direction and the current reverses in the right-hand winding to release the relay. lIrne effect of the current in the middle winding overcomes the effect of the current in the right-hand winding and relay 225 remains operated.

The interrupter at the main or attended station then removes ground from the lead 14 which causes the release of relay 59 in Fig. 6 and relay 226 in Fig. 5. Relay 225 thereupon releases to stop the bell signal 24.1 from ringing and causes relay 15 (Fig. 3) to reoperate which in turn releases relay v to close the circuit to relay 24. If ground is found on Contact No. 1 oi the selector Sa relay 2li operates. Ground, however, in the present description has -been applied to the contact No. 3 of the selector Sa so that, under the control of the interrupter, the selector is advanced from position No. 1 through position No. 2 and thence to position No. 3.

When contact No. 3 of selector `Sa at the auxiliary station is reached by the brush b, relay 24 operates in series with the right-hand winding of relay i1 lwhen relay 8|) releases. relay 226 (Fig. 5) to operate in a circuit extending from grounded battery |3, conductors i4 and 21|, winding of relay 222, conductor 244, front contactl and armature of relay 24, conductor 245 to ground. Relay 225 operated, transfers the line circuit from battery I3 to ground at its lefthand armature causing relay 221 to release. Relay 42 (Fig. 6) thereupon releases.

When relay 49 (Fig. 6) releases as described above, ground is supplied to contact No 3 of the selector Sm Which operates relay |52 and locks this relay to ground at the recheck key 61. Re-

lay |2 operated, lights lamps |55 and 56 andl opens the lead from contact No. 3 of the selector Sm.

The interrupter continues to operate and during the first ten pulses causes the alarm circuit to function in a manner -similar to that described for the first pulse. to position No. 1G, a circuit is completed to the winding of relay 59 which relay operates on release of' relay 49 and locks up to ground at the' left-hand armature and back contact of relay 45. Relay 5S operated, transfers the lead 95 This causes- When the selector Sm stepsV from relay 49 which normally goes to the rotary magnet 94 to the release magnet |96. Relay 59 also prepares a circuit for relay |91 which circuit is completed to ground at the inner right-hand armature and iront contact of relay 49 so that when relay 49 operates relay |01 will operate.

At the auxiliary station, relay 88 operates by way of its left-hand winding as follows: Ground is supplied by relay 86 when this relay releases, to the brush d of the selector Se which causes relay 88 to operate when the selector reaches position No. lO. Relay 69 operated, transfers the lead 89 from relay 86 which normally goes to the rotary magnet 85, to the release magnet ||3. Relay 98 locks up by way of its left-hand winding to ground on the front contact and inner right-hand armature of relay 21.

The eleventh pulse from the interrupter causes relay 49 (Fig. 6) to operate and complete an energizing circuit for relay 226 (Fig. extending from grounded battery, right-hand winding of relay 226, conductor 26|, front contact and inner left-hand armature of relay 49 to ground on conductor 262. Relay 226 operated, causes relay 225 (Fig. 5) to operate which in turn, releases relay 19 (Fig. 3). Relay 89 operates upon the release of relay 19.

When relay 49 (Fig. 6) operates on the eleventh pulse, release magnet |06 is operated from ground at the outer left-hand armature and front contact of relay 49, conductor 96, right-hand armature and front contact of relay 59, to grounded battery through the winding of release magnet |96. This causes the selector Sm at the main station to release and open its off-normal contacts |9| in the circuit to the winding of relay 41. Relay 41 remains locked up to be released later when relay 69 releases.

When relay 89 (Fig. 3) operates on the eleventh pulse, ground is supplied to the release magnet H3 of the selector Sa at the auxiliary station causing the release of the selector. At its righthand armature, relay 8|] closes an energizing circuit for the right-hand Winding of relay 88. Re-

lay 88 releases when relay 89 releases which deenergizes the right-hand winding of relay 88. The left-hand winding of relay 88 was deenergized when the selector and relay 21 released.

When the eleventh pulse from the interrupter released the selector Sm at the main station, ground was also supplied from relay 49 to the winding of relay |91 which relay operated and supplied ground at its contacts |2| to relay 64. Relay 64 cannot operate while ground remains Connected directly to relay |91 but will operate in series with relay |81 as soon as relay 49 releases to remove this ground. When relay 64 does operate, ground is removed from

relays

41, 69 and 59 causing them to release. Relay 60 released, disconnects ground from the start lead 68 to stop the interrupter and supplies ground to short circuit relay ||l1 causing this relay to release and in turn release relay 64.

When ground Was present on the lead I8 due to the rectifier failure at the auxiliary station, relay 24 (Fig. 3) operated in series with relay I1 through its right-hand winding. Relay I1 locked up through its left-hand Winding from battery 9| by way of the right-hand armature and back contact of relay 96. nects resistance |6 from the grounded lead I8 which causes relay |2 to release. When relay 80 (Fig. 3) releases and opens the circuit to relay 24 causing this relay to release, relay 22D (Fig. 5) releases.

Relay |1 operated, discon- Rechecking alarm signals When it is desired to verify the lamp signal such as |05, |31, |49 and |52 received from the auxiliary station, the recheck key 61. (Fig. 6) at the main station must be operated to cause relay 226 (Fig. 5) to operate by way of its left-hand winding over conductor |51. Key 61 operated, also releases the selector Sm and removes ground from relays |02, |36, |48 and |5| releasing them if operated. The lamp signals |95, |31, |49 and |52 are accordingly extinguished.

Relay 226 operated, holds relay 221 operated and operates relay 225. Relay 225 operated, operates slow-to-operate relay 21D in approximately 5 seconds which then operates relay 21| over an obvious energizing circuit. Relay 225 also releases relay 19 to cause relay 80 to operate but the selector Sa does not operate because the circuit to the rotary magnet is open at the righthand armature of relay 220. When relay 21| operates, relay 99 operates to release the selector if locked up and the relays |1, |35, |41 and |56 which may have been locked up. Relay 21| s slow to release with sufficient delay so that when relay 225 releases to release relay 210 and to reoperate relay 19 which in turn releases relay 89, relay 96 is still operated when relay 8D releases. Then relays 21| and 99 release and the selector remains released. The release of relays |1, |36, |41 and |56, if operated, starts the alarm circuit operating again and the same lamp signals such as |95, |31, |49 and |52 will be relighted.

It is evident from the foregoing descriptions of the cable circuit and open wire systems that the occurrence of a failure at the unattended station, in each case, causes ground potential to be applied to a particular terminal of a selector switch thereat and a general signal to be transmitted over the interconnecting circuit to the attended station. The occurrence of the failure also causes a relay interrupter circuit at the attended station to start functioning to drive a selector switch thereat and also to interrupt the interconnecting circuit which causes the selector switch at the unattended station to operate in step with the selector switch at the attended station and hunt for the grounded terminal. Upon the arrival of the selector at the unattended station at the grounded terminal, the selector at the attended station has reached a corresponding terminal with which there is associated a signal control device which operates and causes a lamp signal to be lighted. The lamp signals at the attended station may be differently colored in order to diierentiate between minor and major trouble conditions which exist at the unattended station.

It is to be understood that the line circuits interconnecting the two stations are also used for communication purposes between the stations it being only necessary for the attendants to associate their telephone equipment (not shown) with the interconnecting line circuit by way of jacks which are normally associated with the line circuit. Impedance coils 58 and 232 (Fig. 5) with their associated condensers assist in preventing interference between the telephone, telegraph and alarm circuits.

What is claimed is:

1. In a system for transmitting alarm signals between repeater stations, a rst station, a second station, a normally energized circuit interconnecting said stations, a rst and a second relay included in said circuit, a selector switch at said first station having a plurality of terminals, a selector switch at said second station having a corresponding number of terminals each of which is associated with a signal control device, alarm originating means at said Iirst station, means responsive to the operation of said alarm originating means for marking one of the terminals of the selector switch at said rst station and for altering the electrical characteristic of said interconnecting circuit to cause the actuation of said first relay, an interrupter at said second station responding to the operation of said first relay to step the selector at said second station, means responsive to the operation of said interrupter for again altering the electrical characteristic of said interconnecting circuit to effect the actuation of said second relay, means controlled by said second relay for stepping the selector at said rst station and causing it to hunt for the marked terminal, and means operating in response to the arrival of the rst station selector at a marked terminal for similarly marking a corresponding terminal of the selector at said second station to cause the operation of the signal control device associated therewith.

2. In a system for transmitting alarm signals between repeater stations, a lirst station, a second station, a normally energized circuit interconnecting said stations, a marginal relay and a normally operated relay included in series in said interconnecting circuit, a selector switch at said rststation having a plurality of terminals, a selector switch at said second station having a corresponding number of terminals each of which is associated with a signal control device, alarm originating means at said rst station, means responsive to the operation of said alarm originating means for marking one of the terminals of the selector switch at said first station and for altering the resistance of said interconnecting circuit to cause the operation of said marginal relay, an interrupter at said second station responsive to the operation of said marginal relay to step the selector at said second station, means responsive to the operation of said interrupter for opening said interconnecting circuit to eiect the release of said normally operated relay, means responsive to the release of said normally operated relay for causing the selector at said first station to hunt for the marked terminal, and means operating in response to the arrival of the first station selector at a marked terminal for similarly marking a corresponding terminal of the selector at said second station to cause the operation of the signal control device associated therewith.

3. In a system for transmitting alarm signals between stations, a first station, a second station, a circuit interconnecting said stations and extending between battery potential at said first station and ground potential at said second station, a normally energized relay and a second relay having a pair of normally energized differential windings, the winding of said rst relay and one of the windings of said second relay being included in said interconnecting circuit, a selector switch at said rst station having a plurality of terminals, a selector switch at said second station having a corresponding number of terminals each of which is associated with a signal control device, alarm originating means at said first station, means responsive to the operation of said alarm originating means for marking one of the terminals of the selector switch at said rst station and for connecting ground potential to said circuit at said rst station in place of the battery potential to cause the release of said normally energized relay, an interrupter at said second station responsive to the operation of said first relay to step the selector at said Second station, means responsive to the operation of said interrupter for connecting battery potential to said interconnecting circuit at said second station to cause said second relay to operate, means responsive to the operation of said second relay for causing the selector at said first station to hunt for the marked terminal, and means operating in response to the arrival of the first station selector at the marked terminal for similarly marking a corresponding terminal of the selector at said second station to cause the operation of the signal control device associated therewith.

4. In a system for transmitting alarm signals between stations, a first station, a second station, a normally energized circuit interconnecting said stations, a relay included in said normally energized circuit, a selector switch at said first station having a plurality of terminals, a rotary magnet for operating said selector switch, a selector switch at said second station having a corresponding number of terminals each of which is associated with a signal control device, alarm originating means at said rst station, means responsive to the operation of said alarm originating means for marking one of the terminals of the selector switch at said iirst station and for causing said connecting circuit relay to function, an interrupter at said second station, relay means controlled by said connecting circuit relay for causing the operation of said interrupter, means controlled by said interrupter for operating the rotary magnet of said second selector switch to cause said selector switch to operate,'means also controlled by said interrupter for altering the electrical condition of said interconnecting circuit, means responsive to the altering of the electrical condition of said interconnecting circuit for operating the rotary magnet of said iirst selector switch to cause said selector switch to hunt for the marked terminal, and means operating in response to the arrival of the first station selector switch at the marked terminal for causing the operation of the signal control device associated with a corresponding terminal of said second station selector switch.

5. In a system for transmitting alarm signals between stations, a first station, a second station, a first relay having an armature, a back contact and a grounded front contact, a battery at said rst station, a relay at said second station, a circuit interconnecting said stations extending from a terminal of said battery at said lirst station to a ground connection at said second station by way of the armature and back contact of said iirst relay and an operating winding of the relay at said second station, whereby the relay at said second station is normally operated, alarm originating means at said iirst station, means responsive to the operation of said alarm originating means for operating said iirst relay, whereby the armature of said rst relay disengages its back contact and engages its front contact to cause the battery connection to said circuit to be opened and a ground connection substituted therefor, whereby the relay at said second station is released, and a signal at said second station responsive to the release of the relay at said second station.

VICTOR E. ROSENE.