US1852647A - Telephone system - Google Patents

Description

April 5; 1932- J. w. GODERHAM 1,852,647

TELEPHONE SYSTEM Filed June 6, 1930 /NVE/VTUR J W GUDDERHAM Patented Apr. 5, 17932 UNITED STATES PATENT OFFICE p JOHN W. GOODERHAM, OF LARCH'MMONT, NEW YORK, ASSIGNOR TO BELL TELEPHONE LABORATORIES, INCORORATEDLF NEW YORK, N. Y., A CORPORATION OF NEXV Yom:

TELEPHONE SYSTEM Application nea June e, 1930. seriaino. 459,515.

This invention relates to telephone systems and particularly to the identification of the calling station on a party line.

The objects areto enable the performance of a speedy and reliable test of a party line to ascertain the calling substation, to enable this test without encumbering the line with ground or other interfering connections during conversation, and to otherwise improve systems of this character.

According to this invention, each of the substati'ons on a four-party line is equipped with an alternating currentrelay selectively responsive to current of a particular frequency. vThe central office is provided with four sources of alternating current, each of a frequency corresponding to'one of the substation relays, together with means for applying these sources in succession to the line to make the identifying test. When the source corresponding to the relay at they call-v The invention is illustratedin the ac`com' panying drawing, which shows a party line terminating in a line .finder switch together with means at the central ofl'ice for performing the identification tests and for selectively 5 operating the message registers. i n

The subscribers line 21 has vfour substai tions A, B, C and D. These stations are equipped respectively with alternating current responsive relays 1, 2, 8 and 4. These i0 relays are inductively connected to the line by means of the transformers 5, 6, 7 and 8 `respectively. Each relay attracts its armature in response to alternating current of` a par` ticular frequency, which differs' from the fre- .quency to whichV any of the other relays is responsive. At the central ofhce the line ter- `minates in the bank of a line finder switch F, which is diagrammatically illustrated by the brushes 22 to 28 inclusive.U The line finder ,F is directly connected' to a selector switch S having the brushes 65, 66 and 67, which is also illustrated in part diagrammatically. The selector switch S has access to succeeding selectors (not shown). v

The line finder and selector disclosed in this system may be of the panel type similar to the one described in the patent to Craft et al., No. 1,123,696, granted January 5, 1915. The control and operating circuits for a selector switch of this character are shown and described in detail inthe patent to Kopp No. 1,589,402, granted June 27, 1926, and also shown in the patent to Stern et al., No. 1,395,- 977, granted November 1, 1921.

The stations A, B, C and D are provided at the central office with individual message registers 62, 62, 63 and 64, which are selectively operated to assess calls againstV the corresponding stations on the line. The registers are selected as the result of an identication test performed at some convenient time after the subscriber initiates the call. The test is madel by meansof the alternating current sources 52, 53,154 and' 55, each of a different frequency, and the results of this test are recorded on the relays 57, 58, 59 and 60.

A detailed description will now be given, and it will be assumed for this purpose that the subscriber at station A initiates a call. In response to the initiation of the call, the line finder F operates to seize the calling line 21. Thereupon, the subscriber manipulates his impulse transmitter 9 to set up the called designation in a register sender (not shown) at the central office. The register sender proceeds to control the selector switch S and ,succeeding switches to extend the connection to the called subscribers line as is fully described in the above-mentioned patents to Kopp and to Stern et al.

' When the called party answers, the direction of current flow over the trunk with whose terminals the brushes 65, 66 and 67 of the selector S are in contact, is reversed, thereby causing the operation of the polarizedsuper- Vvisory relay 33. `At this time the sequence switch has advancedto some position such as position 13, in Awhich it remains during conversation. As soon after ,the relay 33 operates as the interrupter 44 closes its right magnet 46 to control the testing of the linel through conductors 72 and 73 tothe subcontacts, a circuit is completed from battery through the winding of relay 34, right contacts of said interrupter, contacts of sequence switch spring 38, contact of relay 33, upper contact of sequence switch spring 38, contact of relay 33, upper contact of sequence switch spring 35, to ground at the Contact of sequence switch spring 36. Relay 34 operates and locks through its upper contact, contact of sequence switch spring 37, thence as above traced to ground at sequence switch spring 36. As soon after relay 34 has operated as the interrupter 44 closes its left contacts, a circuit is completed from battery through the winding of relay 29, uppermost contact of relay 31, contacts of sequence switch spring 68, lower front contact of relay 34, left contacts of interrupte'r 44, thence as above traced to ground at sequence switch spring 36. Relay 29 operates and locks in a circuit from Ybattery through its winding, uppermost contact of relay 31, inner lower contact of relay 29 and contact of relay 33 to ground at sequence switch spring 36.

The brushes 47 to 51 inclusive of the stepping switch S-1 are now advanced by the alternate operation and release Vof the stepping 21. With the brushes in any one' of positions 1 to 8 inclusive, position 1 being the normal position, a circuit is closed, after relay 29 is operated, through the winding of the magnet 46 each time the continuously driven interrupter 30 closes its contacts. This circuit may be traced from `battery through the winding of the magnet, brush 48, positions 1-to 3, conductor'69, innerupper contact of relay 29 to ground at the contacts vof the interrupter 30. The release of the magnet 46 each time the circuit is opened causes the advance o f the brushes one step. After the brushes are advanced beyond position 8, theV magnet 46 is no longer under the control of the interrupter 30.

With the stepping switch S-Y-l in position 2, a circuit is closed from battery through the lower winding of relay 32, brush 49, conductor 70 to ground through sequence switch springs and 36. Relay 32 operates and locks through its lower winding and inner lower contact to the grounded conductor 70. Relay 32 prepares a'circuit for: operating the calling subscribers message register after conversation has been completed. Y

With the stepping switch in position 2, 'another circuit is closed from the grounded source ofalternating current 52 through the brush 50, primary winding of the transformer 7,1 to ground. The secondary `winding of the transformer 71 lis connected scribers line 21.v The circuit over the subscribers linemay'be traced vfrom the -rightthand terminal'oflthe secondary winding of said transformer overrconductor 72, :upperhand terminal of the secondary winding of transformer 71. Current flowing from the source 52 through the primary winding of transformer 71 induces current of the same frequency in the secondary winding and this current flows over the subscribers line and through the transformer 5. It will be assumed that the frequency of source 52 is such as to cause the operation of relay 1 at the calling substation vA. Relay 1 operates and completes a circuit from ground through its armature and contact over the tip conductor 74, thence as above traced to conductor 72, through a portion of the secondary winding of transformer 71 through 'the winding of relay 56 to battery. A parallel circuit is completed from the grounded armature of relay 1 through the transformer 5 and induction coil 10, switchhook contact, talking transmitter and impulse transmitter 9 over the ring conductor 75, thence vto conductor 1 73 and 4through the other Aportion of the secondary winding of transformer 71 and the winding of relay 56 vto battery. Relay 56 operates in this circuit andcloses a circuit from ground through its armature and contact, brush 51 in position 2, conductor 76, winding of the register relay 57 to battery. Relay 57 operates and locks 'in a circuit from battery through its winding and left contact, conductor 77, to ground at the lower contact of relay 32.

The stepping switch S--lcontinues'its ad- Vance through positions 3, 4,5, 6, 7 and 8 and in so doing applies the sources-53, -54 and in succession to the transformer 71. However, this is without effect since therelay 1 responds only to the source 52 andfsince only the substation A is calling.

When 'the stepping'switch S-1 reaches position 9, a circuit is closed from battery through the winding of relay 31, brush 49, to the grounded conductor V70. Relay 31 opcrates and locks to conductor 70. Relay 31 at its uppermost contact opens the circuit of relay 29, and this relay releases. Relay 31 in operating connects ground potential through its inner upper contact overconductor 78, contact and arma-ture of 'magnet 46,

brush 47 is associatedareconnected together the switch continues to advance `until it has reached its normal position 1. The apparatus remains in this position during conversation.`

When the called subscriber replaces his receiver on the switchhook, relay 33 releases, and sequence switch 45 is advanced from the talking position to some subsequent position, suchas position 17, to cause the operation of the message register of the calling The release of relay 33 opens the circuit of relay 34, and the latter relay releases. Relays 31 and A32 are'now held in a circuit though their windings and locking contacts, conductor 70, back contact of relay 34, brush 47, position 1, armature' and contact of the magnet 46, conductor 78, through the inner upper contact of relay 31 to ground. While the sequence switch 45 is advancing from position l to position 17, a metering circuit is closed from battery through the Vresistance 79, upper contact of relay 32, contacts of sequence switch spring 80, lowermost contact of r-elay 31, conductor 81, right-hand armatures and back contacts of relays 60, 59 and 58 in series, right armature and front contact of relay 57,

V brush V28, through the winding of message register 61 to ground. The register 61 operates and charges the call against substation A.

When the sequence switch reaches position 17 and as soon thereafter as interrupter 43 closes its contacts, a circuit is completed from battery, through winding of relay 34, contacts of sequence switch springs 41 and 42 to ground at the contacts of interrupter 43. Relay 34 operates and opens the holding circuit of relays 31 and 32. Relay 34 may be held energized in the manner shown in detail in the above-mentioned patent to Kopp to permit the release of relays 31 and 32 as the sequence switch 45 advances to subsequent positions. The release of relay 32 opens the holding circuit of relay 57. From this point, the release of the line finder and selector switches takes place in any well-known manner, such as explained in the above mentioned patents to Kopp and to Stern et al.

Assume next that the call is initiated at substation B. In this casethe relay 56 does not operate when the stepping switch moves into position 2 since current induced by the source 52 does not cause the operation of relay 2 at the calling substation. In position 4 of the stepping switch however, current from the source 53 is connected to the transformer 71, and the induced current in line 21 is of the proper frequency to operate the relay 2 at substation B. Relay 2 applies ground potential to the tip and ring conductors of the line 21 in the manner already explained in connection with substation A, and relay 56 operates. Relay 56 applies ground potential over brush 51, conductor 82, winding of relay 58 to battery. Relay 58 operates and locks through its left contact to the grounded conparty. holding ter 64 operates and charges the call to substation D.

duetor 77. The switch S-l continues to step, and sources 54 and 55 are connected to the transformer 71, butnothing further happens since these sources are not of the proper frequency to operate relay 2. At the end of con-37.n versation when the sequence switch 45 is passing from position to position 17, the metering circuit is completed from battery through the resistance 79, thence as traced over cony ductor 81, right baclr contactsof relays 60 anda, 59, right front contact of relay 58, brush 27, winding of message register 62 to ground. The register 62 operates and charges the call to substation B.

Assume next that the call is initiated byxf substation C. In this case nothing happens when the sources 52 and 53 are connected to the transformer 71. However, when the stepping switch S-l reaches `position 6, source 54 is connected to the transformer and the current induced in the line 21 is of the proper vfrequency to operate relay 3 at the calling substation C. Relay 3 causes the operation of relay 56as explained, and relay 56 completes a circuit over brush 51, conduc-tm tor 83, winding of relay 59 to battery. Relay 59 operates and locks through its left contact to the grounded conductor Y7 7. Subsequently, when the sequence switch is moving from position 15 to position 17, the metering cir-CL cuit is completed over conductor 81, right back Contact of relay 60, right front contact of relay59, brush 29, winding of message register 63 to ground. The register 63 operates and charges thecall to substation C. '515.100

Assume finally that the call is initiated at substation D. In this instance, the stepping switch first applies the sources 52, 53 and 54 without effect. As the switch reaches posi-I tion 8,-source is connected to the trans-:mi former 71, and the current induced in the line 21 is of the proper frequency to cause the operation of relay 4 at substation D. Relay 4 applies ground potential to the line to cause the operation of line 56. Relay 56 closes alim circuit from ground over brush 51, conductor 84, through the winding of relay to battery. Relay 60 operates and locks to the grounded conductor 77 As the sequence switch 45 passes from position 15 to position 17, the metering circuit is completed over conductor 81 to the right front contact of relay 60, brush 25, windingof register 64 to ground. Regis- While the invention has been illustrated in connection with a particular type of system,

it is to be understood that it is not so limited but may be embodied vin various kinds of systems. 'l 125 What is claimed is: i

' 1. In a telephone system a line having a pluralityof stations thereon, relays, one at each. station, said relays being responsive each to current of a different frequency,

fir

plurality or stations thereon, relays, one at means for applying to said line currents 'of different frequencies, and means controlled bythe operation of said relays for identifying said stations.

2. In -a telephone system a line having a each station, said relays being responsive each to alternating current of a dilierent frequency, a plurality of sources of alternating current, each of a different frequency, means for connecting said sources to said line, and means controlled by the operation of said relays for identifying Isaid stations.

3. The combination in a telephone system of a line having a plurality of substations thereon, relays, one at each of said stations,

Ieach of a frequency .corresponding to said relays being responsive each to alternating current of a different frequency, va plurality of sources of alternating current, one of said rela-ys, means for successively applying .said sou-roes yto said line in a 1definite order, and vmeans responsive to the operation of any one of said relays for identifying the cor- Q5 responding substation.

'5&0 current'of .a different frequency,

VM585 ing substation in said test circuit, means for connecting said sources of current to said test circuit, and means responsive to the operation of one of said relays in lthe test circuit Vfor identifying the corresponding substation. .5. In a telephone system a subscribers line having ka plurality of substations thereon, relays, one at each of said stations, Vsaid relays being responsive each Yto alternating current .of a different frequency, message registers, one for each of said substations, a plu- :ralityfof sources ofalterna'ting current, each of a frequency cor-responding to one of said relays, mea-ns :for applying 'said sources to the line in succession, means controlled by said relays for identifying the calling substation, ,and means controlledA by the identifying means for Vselectively operating the message register individual to the calling substation. y6. In `a telephone system, a line having a number of stations thereon, relays, one at each .of said stations, said relays being responsive each to current of a. different frequency, a number of sources of current. eacn of a different frequency, means 'for connecting said sources to the line to selectively operate the relay at thecalling station, said relays `in 4operating serving to yapply potential `to said line,;and means responsive to the ap- -`plication of :potentials'by said relays to said :line vfor identifying said stations.

7. In a telephone system, a line having a plurality of stations thereon, relays, one at each station, said relays being responsive each to current of a different frequency, a test circuit including the conductors of said line, means under the control of a calling subscriber for closing the test circuit to render effective the relay at the calling substation, means for selectively operating said relays, circuits closed by said relays in operating for applying ground potential to said test circuit, and means responsive to the application of ground potential to said test circuit for identifying said stations.

8. The combination in a telephone system of a line having a plurality of substations thereon, relays, one at each of said stations, said relays being responsive each to -alternating current of a different frequency, a pluralit-y of sources of alternating current, each of a frequency corresponding to one of said relays, means including a step-by-step switch for successively applying said sources to said line in a definite orde-r, and means responsive to the operation of any one of said relays for identifying the corresponding substation.

In Witness whereof, hereunto'subscribe my name this 4th day of J une, 1930.

JOHN W. GUODERHAM

Images