US1632051A - Telephone system - Google Patents

Description

1,632,051 W. WHITNEY TELEPHONE sys'rsu v Filed July 2a, 1926 2 Sheets-Sheet 1 June 14, 1927.

Jl me 14. 1921. 1,632,051

. w. WHITNEY TELEPHONE SYSTEM Filed July 28, 1926 a Sheets-Stieet 2 Patented June 14, 1927.

UNITED STATES PATE T OFFICE; Y

WILEY I EY, 0F nnsr ORANGE, NEW J RS Y, ASSIGNOR T0 BELL TELEPHONE LABORATORIES, INCORPORATED, OF NEW Yomg'N, Y., A OORPoRATIjoN OF NEW YORK.

TELEPHONE SYSTEM.

Application filed July 28,

This invention relatesto telephone systems, and more particularly to improvements in the establishment and supervision of connections over straightfoiwvard trunks;

Heretofore in trunking systems of this type it has been customary to provide, at the incoming ends of the straightforward trunks, means for associating therewith a circuit, containing a dialing equipment anda B operatorstelephone set, which is common to a plurality of such trunks. A sequence circuit is often interposed between the trunks and the common equipment for the connection of said equipment with the straightforward trunks in the order in which such trunks are taken for use. Trunks of this type may terminate in plugs at the incoming end andbe equipped for extension to various kinds of wanted subscribers lines. Con: nection may be extended either directly to a subscribers line, or through intermediate interofiice trunks leading to operators positions at a distant exchange or to automatic equipment of a distant exchange. From theseoperators positions a wanted subscriber may be reached through a manually completed connection, or through automatic switches that may be operated by the actuation of the B opera-tors common dialing equipment to associate a straightforward trunk with the wanted subscribersline.

According to the present invention there is provided an arrangement whereby the common equipment,including a dial and a B operators telephone, is automatically associated with and preparedfor use with a straightforward trunk when said trunk is seized at. the originating end and whereby a signal consisting of a plurality of distinctive tone impulses is automatically produced and transmitted to the operator at the call originating end and to the B operator when the connection between the common equipment and the seized trunk is completed.

According to another aspect of the invention the usual ringing relay is employed for 1926. Serial No. 125,367. X

7 involving said trunk.

Moreoverjthere is provided means whereby the usual guard and disconnect lamp as-' sociated with a straightforward trunk is not locked in actuated condition when a trunk is seized but is free to release if the operator at the originating end abandons the call before the common equipment is connected totthe trunk. v

The invention has been illustrated in the accompanying drawings, in which 1 shows the incoming end of a straightforward trunlz arranged in accordance with this invention. A port on of sequence circuit is also shown in this figure whereby the common equipment may be'connected in succession to seize trunks, while Fig. 2 shows this common equipment which includes, besides the operators telephone setand dial, an arrangement for producing a plurality of tone impulses.

Referring now in general to the circuit arrangements shown, a straightforward trunk l incoming from a distant exchange terminates in a plug 2 whereby connections may be extended to various types of lines, for example, to jack 4 of a tandem trunk that may terminate at a distant exchange at an incoming operators position or automatic equipment, or through a jack 3 directly to a wanted subscriber. This trunk; 1 is provided with a guard and disconnect lamp 5 for the supervision of a call over this trunk and a sequence circuit through which the B operators telephone set 6 and a dial 7 may be associated with the trunk. Of this circuit only a relay arrangement 8 individual to trunk 1 hasbeen shown together with a relay arrangement 9 which is common to a plurality of trunks, it being understood that each trunk such as 1 ofthe same group is equipped withan individual relay arrangement such as8. This last mentioned common equipment 9 includes'a pilot lamp 10. The common equipment shown in Fig. 2 includes besides the B operators set 6 and dial 7 a tone source 12 and a relay arrangement 13, whereby two impulses of tone may be produced for transmission to the call originating operator and to the telephone set 6, and also a relay arrangement .14: whereby the common equipment may be manually disconnected from the trunk 1. A relay arrangement for flashing the guard and disconnect lamp 5 shown in Fig. 2 will be hereinafter described.

To clearly bring forth the various features of this invention a description will now be made of a connection extending over trunk 1 to a manual subscriber and to an automatic subscriber and a description of the functions taking place when the operator at the originating exchange abandons a call over trunk 1. Assuming then that the operator at the originating exchange has seized trunk 1, in a manner well known inthe art by establishing a battery connection for the conductors of trunk 1, relay will operate over a circuit from the conductors, retardation coil 21, left winding of relay 20 to ground and middle winding of relay 20, armature and back contact of relay 23 to ground. The operation of relay 20 closes an obvious circuit for relay 2 which in operating closes circuit for the operation of relay 25 as follows: Battery, winding of relay 25, lower outer armature and back contact of relay 26, armature and front contact of relay 2%- to ground. Relay 25 in operating opens the tip conductor of trunk 1 at its upper outer armature and back Contact and provides a circuit for the operation of relay 26 as follows: Battery, winding of relay 26 upper inner armature and back contact of relay 26, upper armature and back contact of relay 2?, upper inner armature and front contact of relay 25 to ground. Relay 26 in operating closes a looking circuit for itself through its upper makebefore-break contacts to'ground at the armature and front contact of relay 24, and closes a circuit for the lighting of guard lamp 5 as follows: Batte y, lower outer armature and back contact of relay 28, resistance 29, lower inner arn'iature and front Contact of relay 26. lower outer arn'iature and back contact of relay 2?, lamp 5 to'ground. lhe lighting of lamp 5 indicates to the B oporator that trunk 1 has been seized.

If the common equipment shown in Fig. 2 has not been seized by any other trunk at this time, battery will be supplied for the operation of relay 30 over the following circuit: Battery, winding of relay 30, enter lower armature and front contact of relay 2, armature and front contact of relay 21 to ground. The operation of relay 30 closes a circuit for the operation of relay 31 as follows: Battery, winding of relay 31,

lower armature and front contact of relay 30 through lower make-before-break cont-acts of relays corresponding to relay 30 individual to other trunks through the winding of relay 32, armature and back contact ofrelay 33 to ground. This circuit also causes the operation of relay 32, hichin operating closes an obvious circuit for relay 33 that removes the ground from the previously traced circuit and is locked with the relays 32 and 31 through the front contacts of relay 32 to ground. Relays 32 and 33 are provided to insure that the lowest numbered of the waiting trunks will be next connected to the common equipment when released from the last trunk in the group in a manner which will be set forth hereinafter. The operation of relay 31 associates the common tip and ring conductors from the operators telephone set 6 with the tip and ring conductors of trunk l at its outer upper and lower armatures and front contacts.

Itshould be understood that the operators telephone set 6 is connected through the plugs and jacks shown connected to the common talking circuit through the repeating coil 3 1 when. the B operator is in attendance at this position. Relay is, therefore, at such times operated by a circuit from battery, winding of relay through the transmitter, the primary of the repeating coil 34: to ground. Relay 35 in operating causes the operation through obvious circuits of relays 36 and 37, so that a talking circuit from the operators telephone set ('3 is normally extended to the upper and outer lower armatures of relays, such as 31, except that this circuit is broken at the contacts of relay at"? until required as will be hereinafter described. The operation of relay 31 closes a circuit for relay 38 as follows: Britt-my, resistance 29, inner lower armature and front contact of relay 26, enter lower armature and back contact of relay 2?, middle upper armature and front contact of relay 31, makebefore-break contacts of relay 39, winding of relay 38 to ground. The operation of relay 3S closes an obvious circuit for the operation of relay 39, which in operating closes an obvious circuit for the lighting of pilot lamp 10 to indicate that a trunk is being connected to the. common equipment. This relay in operating also transfers the control over the operation of relay 38 from the battery at relay 28 to battery through the winding of relay 25 through the inner upper armatures and front contacts of relays 31 and 30 and the outer upper armature and front contact of relay 39.

Another circuit closed by the operation of relay 39 is that for the operation of relay 40 which may be traced as follows: Battery, lower outer armature and back contact of relay28, resistance 29, lower inner armature and front contact of relay 26, lower outer armature and back contact of relay 27, upper middle armature and front contact of relay 31, upper inner armature and front contact of'relay 39', right hand armature and front contact of relay 36, winding of relay 40 to ground. It should be noted'that this "relay 40 is in a connection to ground parallel to the connection toground of lamp 5. hen relay 40 attracts its armature an obvious circuit will be closed for'the slow to operate relay 42, which in attractingits armature closes an obvious circuit for the operation of slow to operate relay 43 on the operation of this last mentioned relay a connection is closed to ground at its armature and front contact for'theshunting of relay 40 and lamp 5. Relay 40 is released and lamp 5 is'extinguished. On therelease of relay 40 relays 42 and 43 are released in succession and on the release of relay 43 the short-circuit for relay 40 and lamp 5 is re moved so relay 40 is reoperated and lamp 5 is again lighted. This cycle of operations of relays 40, 42 and 43 is continuous, so that lamp 5' alternately becomes lighted and extinguished to indicate to the B operator that the common equipment has been ciated with the trunk 1.

It will be noted that on the operation of relay 31 a circuit is closed for the operation of relay 45 as follows: Battery, winding of relay 25, upper inner armatures and front contacts of relays 30 and 31, left hand armatureand front contact of relay 36, outer right hand armature and back contact of relay 72, winding of relay 45, normal makebefore-break contacts of this relay through the lower inner armature and back contact of relay 47 to ground. Relay 45 in operating provides a locking circuit for itself independent of the ground at the relay 47, through its armature and front contact to ground. This relay 45 in operating also closes an obvious circuit for the operation of relay 48; Relay 48 in operating provides a circuit from the tone device 12 to the tip and ring conductors of trunk 1, the primary of tone coil 49 of tone device 12 being connected to ground through the inner right hand armature and front contact of relay 48 and ri ht hand armature and back contact of relay 50, while the secondary of the tone coil 49 is connected to the two outer right hand armatures and front contacts of relay 48, the upper and lower outer armatures and back contacts of relay 47, upper outer and lower armatures and frontv contacts of relay 37, upper outer and lower armatures and back contacts of relay 51, upper andlower outer armaturesandfront contacts of relay 31 through the upper "and lower armatures and back contacts of rela 53 winding of relay'7 5 onthe ring through the right hand windings of the repeating coil 54 to battery and ground. Relay does not operate in this circuit due to the inclusion of a condenser-at the back coir tact of theupper armature of; relay 51. A connection i s-also established from the secondary of the coil 49 of the tone device to the upper armatures and back contacts of relay 47to the primary winding of the repeating coil 56' associated with the receiver of the operators telephone set 6, so that a tone will now be transmitted through the 'repeating'coil 56 t0 the operators telephone frontcontactto ground for the primary of the repeating coil 79 so'that a tone is -again transmitted to the operator at the distant end of trunk 1 and to the B operators telephone set 6; The operation of relay 58 closes an obvious circuit for the slow to operate relay '59,'which in operating closes an-obvious circuit for the operation of relay 47. The operation of thisrela'y opens the original energizing circuit for relay 45 at its inner lower armature and back contact and also opens the circuit from the secondary of the tone coil 49 to the tip and ring conductors leading tothe trunk 1 and disconnects the repeating coil 56 so that the tone from the device 12 will cease to be transmitted to the two operators. These two impulses of tone indicate to'the B operator and to the operator at the distant end of the trunk 1 that the B operators telephone set 6 has been connected to the trunk 1. This takes place on the operation of relay 47 when the secondary of the transformer 34 is connected through the upper outer and the lower outer armatures. and front .contaots, through two of the contacts of relays 37, 51, 31 and 53 to. trunk 1.

Conversationbetween the operator at the distant end and the B operator may now take place and when the B operator receives the number of the wanted subscribers line she may initiate the desired connection by inserting plug 2 into jack 3 if a local subscriber is wanted. In this case a circuit is established through the sleevesof plug 2 and jack 3 for the operation of relay 62. The operation of relay 62 completes the tip conductor fortrunk 1 to the terminals of plug 2 and jack 3 and closes the circuit for the operation of relay 27 as follows: Battery, lower armature and front co'ntact'of relay 62, windingfof relay 27 to ground. The

operation of relay 27 opens the original en- 7 "ergizing circuit for relay 26 at its upperar- 'mature and back contact and at-i'ts-lower "ou e aware and 1.3840 contact op ns the circuit for lamp '5, which is now extinguished. This relay also closes a circuit for. ringing relay as follows: Battery, winding of relay 65,- lower inner armature and back contact of relay 28, lower innerarmature and front contact of relay 27 armature and front contact of relay 2a to ground.

The operation of relay 65 connects ringing current from source 66 through the ringing trip relay 67, upper middle armature and back contact of relay 28 through the lower armature and front contact of relay 65 to the ring conductor of trunk 1 and a ground through the upper armature and front contact of relay 65 to the tip conductor of trunk 1. This ringing current is transmitted to the subscriber connected to jack 3. It should be noted that ringing is also inductively transmitted through condenser 68 and repeating coil 54 to the outgoing end of trunk 1, so that the operator at this end will hear the ringing of the wanted subscriber.

lVhen the wanted subscriber answers ringing trip relay 67 operates as is well known in the art and by removing the ground from the outer contact of its armature causes re lay 28 to operate from the battery at the lower armature and front contact of relay 62. The operation of relay 28 causes the release of ringing relay 65 and also ringing trip relay 67 and ringing current is thereby removed from the trunk 1. The release of relay 65 establishes a connection for the tip and ring leads between the repeating coil 51- and the plug 2, so that relay will now become operated through the subscribers loop. This relay in operating closes an obvious circuit for the operation of relay 23 and this relay which by attracting its armature applies battery to the tip conductor of trunk 1 to cause a signal indication, as is well known in the art, to be made at the distant operators position, indicating that the called subscriber has answered.

It should be noted, however, that before conversation between the subscriber at the distant end of trunk 1 and the wanted subscriber can take place the B operators telephone set must be disconnected from the trunk. This is done by having the B op erator actuate release key 70. -The operation of key 70 closes a circuit for relay 7-1 as follows: Battery, right hand winding of relay 71, right hand armature and back contact of relay 72, upper inner armature and front contact of relay 37, outer left armature and back contact of relay 73 and key 70 to ground. -The operation of relay 71 closes a circuit for the operation of relay 46 as follows: Battery, armature and front contact and left hand winding of relay 71, makebeforebreak contact of relay 72, right hand winding of relay 46 to ground. The operation ofrelay 4:6 closes a circuit from battery at the ari'nature and front contact of relay 71 to the left hand armature and front contact of relay 46 through theleft hand winding of this relay to ground, and also through the left hand Winding of relay 72 to ground. Relay 72 operates and breaks the original energizing circuit for relay 46 which, however, is now held up from the battery on the armature and front contact of relay 71 through its own left hand armature and front contact. Relay 72 in operating however opens the energizing circuit for relay 71, but before this relay releases a connection from battery at the armature. and front contact of this relay is connected through the left hand armature and front contact of relay 72 to the left hand armature of relay 36, the purpose of which will be explained later. Relay 72 in energizing closes locking'circuit for itself to battery through its right hand winding, inner right hand armature and front contact to the ground at key 70 and the release of relay 71 causes the release of relay 46. The operation of relay 72 also opens the circuit for relay 45, which in releasing causes the release of relay 18 and the release in succession of relays 50, 58, 59 and 47. The release of relay 47 opens the circuit from the operators telephone set 6 to the tip and ring leads of trunk 1 and the temporary battery from the armature and front contact of relay 71 mentioned above causes the release of relays 25', 38 and 39 and extinguishes pilotv lamp 10. Relay 25 now becomes locked in non-operated position due to the battery connected through its make-before-break contacts and upper outer armature and front contact ofrelay 26. The release of relay 25 causes the release of re lay 30 in the sequence circuit and the release of this relay causes the releaseof relays 31, and 33. Upon the release of relay 32 the ground connection provided by relays 32 and 33 is opened for an interval timed by the slow release of relay 33 so that if another relay such as 31 is in a condition to be energizedits circuit will not be completed through the chain contacts of relays such as 30 until the disconnection of the operators set 6 from the present trunk is completed. Upon the reapplication of this ground connection by the release of relay 33 the lowest numbered of the waiting trunks will be next connected to the counting equipment because the circuit of the relay 31 of the lowest numbered trunk will be completed and the circuit of other relays such as 31 will be opened by the energization of the relay corresponding to relay 30 of such lowest numbered waiting trunk. The release of relay 25 also causes the release of relay 53 if the plug 2 has been inserted in jack 3 before the operation of key 70 in which case this relay became operated on the operation of relay 28. The operation of relay 53 in this type of connection is believed of no importance. The con nection from the operator at the distant end of trunk 1 to the wanted subscribers line is now completed through contacts of the re-- lays 53, 25, and 62 so that conversation may now take place between these subscribers. V 1

hen conversation ceases and the wanted subscriber. hangs up his receiver, relay 75 releases, causing the release of relay 23, which removes the battery from the tip eon ductor of trunk 1, causing a .disconnect signal to be received at the distant operators position. This operator thereupon removes the plug from the jack associated with the opposite end of trunk and thus causes the release of relays 20 and 24. The release of relay 24 causes the release of relay 26. This closes a circuit for. thelighting of lam 5 and operation of relay 65 as follows :i attery, winding of ringing relay 65, inner lower armature. and front contact of relay 28, inner lower armature and back contact of relay 26, outerlower armature and front contact of relay 27, lamp 5 to ground. Then the B operator finds lamp 5 lighted, she will remove the plug 2'from jack 3, causing the release of relays 62, 27, 28 and 65 and the circuits are'now in normal con-. dition. In this type of connection the operation of the ringing relay 65 atthistime is of no importance.

If the operator at the distant end of trunk 1 should abandon the call by removing the plug of her cord from the'jack of trunk 1 before the B operator had time to operate her release key 70, the B operators telephone set 6 and dial 7 would be automatically disconnected from the trunk 1,tha,t is, relays 20 and 24 will release and the release of relay 24 will cause the release of relay- 26 and relays 30 and 31. The release of relay 26 causes the release of relay 25. If plug 2 is inserted injack 3, relay 53 will also be released at this time and in that case the lamp 5 will light on the release of relay 26 so that the B operator will now remove plug 2 from jack 3. The release of relays 30 and 31 will naturally cause the release of relays 38and 39, 32.and 33, and relays 45. 48, 50, 58, 59 and 47 so that the common equipment will be restored to normal condition and is now therefore available for use with other trunks.

If the wanted subscriber is one that can be reached only through an intermediate trunk such a trunk terminating, for example, in jack 4, such trunk may be selected by the usual call wire method and the connection established at the distant exchange through the usual manual cord circuit. If an automatic subscriber is desired, the connections will be established at the distant exchange to automatic switches so that the B operator may dial the desired subscribers number. As the means of extending the connection to an automatic exchange subscriber forms nopart of this invention, no showing has been made thereof,nor will any further descriptions be made in this respect, except to show how the B operator may dial such a subscriber. Under these circumstances, on insertion of plug 2 into jack 4, the operations willbe identical to the operations described for the connection through jack 3, except that the ringing will be tripped immediately to cause the operation 1 of relay 28. It will be noted that on the operation of relay 28 relay 53 operates from ground-at the upper inner armature and front contact of relay 25 to the battery ap plied at the upper inner armature and front contact of relay 26. The operation of relay 53 connects the tip of plug 2 to the tip conductor of the common equipment through the upper outer armature of relay 31 independent of relay 25, so that the common equipment is now connected to plug 2. The B operator may now actuate her dial 7 and on the operation of the dial-from normal a ground connection is made to the off-normal contacts of the dial for the operation of relay 73 over an obvious circuit and on the operation of relay 73 a circuit is closed for the operation of relay 51 as follows: Battery, upper outer armature and front contact of relay 26, upper outer armature and front contact of relay 28, upper outer armature and front contact of relay 30, winding of relay 51, right hand armature and front contact of relay 73 to ground. On the operation of relay 51 ground from the middle left hand armature and front contact of relay 73 is connected through the lower armature and front contact of relay 51 to the ring conductor of plug 2 through the trunk connected to jack 4, and a ground is also connected through the pulsing contacts of dial 7and upper inner armature and front contact of relay 51 to the tip conductor of plug 2 and'rthe tip conductor of the trunk connected to 3 jack 4. This second "mentioned connection to ground will be interrupted on the return of the dial to normal in accordance with the digit dialed, to cause the operation of the usual pulsing relays in the automatic switches at the distant end thereby manipulating the switches to select the wanted subscribers number as is well known inthe art. Relays 73 and 51 are released between the digits so that the B operators telephone set 6 will be connected through the induction coil 34 and the talk ing conductors of the plug 2 to the distant switches. This is to enable the transmission of busy tone to the operators telephone set 6 in-case a busy condition is encountered. After dialing is completed, the B operator releases her dial and telephone set by the operation of key 7 O in the manner hereinbefore described and the Subscribers may begin conversation. After the subscribers have finished their conversation the disconnection may take place in the same manner as when a manual subscriber is connected to jack 3. v a

As mentioned in connection with the description of the release of the trunk lwhen the operator at the distant end removes a plug from the jack or trunk 1, relay 65 operates at the same time as lamp 5 is lighted. In this case the splitting of the trunk at the armatures and back contacts of relay 65 may be utilized as a disconnect signal. Relay 65 may therefore serve two purposes, namely, to apply ringing current and to split the conductors of trunk 1 to produce a signal at the distant end of a connector trunk.

lVhat is claimed is:

1. In a telephone system, a trunk, a signal associated with said trunk, an operators telephone set and an impulse sender, means responsive to the seizure of sad trunk for actuating said signal and for automatically associating said telephone set and sender with said trunk, and means efiective incident to the association of said telephone set and sender with said trunk for actuating said signal in a different manner and for transmitting a signal con'iprising a plurality of impulses of tone current to said trunk and t said telephone set.

2. In a telephone system, a trunk, 21 line, a signal associated with said trunk, means for actuating said signal responsive to the seizure of said trunk at its outgoing end, means .for interconnecting said trunk and line, means including a relay responsive to the interconnection of the trunk and line for disabling the signal and another relay under control of said first relay for opening the trunk conductors and applying ringing current to said line, means including another relay responsive to the tripping of the ringing for releasing said second mentioned relay, and means responsive to the release of the outgoing end of the trunk for reactuating said signal and for reactuating said sec ond mentioned relay to reopen the trunk conductors.

3. In a telephone system, a trunk, a line, means for seizing said trunk, means for interconnecting said trunk and line, means including a relay operating in response to the interconnection of said trunk and line for opening the trunk conductors and applying ringing current to said line, means responsive to the seizing of said line for releasing said relay to discontinue the ringing and close the trunk conductors, and means responsive to the release of said trunk for reopcrating said relay to open the trunk conductors without applying ringing current to the line. I

4. In a telephone system, a trunk, an operators telephone set and a dial, a signal associated with said trunk, means responsive to the seizure of said trunk for actuating said signal and for automatically associat ing said telephone set and dial with the trunk, means efi'ertive incident to the automatic association of the telephone set and dial with the trunk for actuating said signal-in a different manner, and means for automatically releasing said telephone set and dial and disabling the signal responsive to the release of said trunk.

5. In a telephone system, a trunk, a line, an operators telephone set and a dial, a signal, means responsive to the seizure-of the trunk for actuating said signal and automatieally associating the telephone set and dial with the trunk, means effective incident to the association of the telephone set and dial with the trunk for actuating said signal in a different manner and for applying a tone signal comprising a plurality of tone current impulses to the trunk and to the operators telephone set, means for associating the trunk with the line, a source of ring ing current, means effective incident to the association of said trunk and line for disabling said signal before applying ringing current to the line and to the trunk and for WILEY WHITNEY.

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