US1217168A - Telephone-exchange system. - Google Patents

Description

C. L. GOODRUM.

TELERHONE EXCHANGE SYSTEM.

APPLlCATlON FILED lAN.20,1916.

Patented Feb. 27, 1917;

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" A/fy C. L. GOODRUMM TELEPHONE EXCHANGE SYSTEM.

APPLICATlON FILED JAN. 20, I916.

Patented Feb. 27, 1917.

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CHARLES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR T WESTERN ELECTRIC COM- PANY, INCORPORATED, 0F NEXV YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed January 20, 1916.

To all whom it may concern:

This invention relates to' telephone 6X-' change systems wherein calling lines are as sociated with idle connecting circuits by means of line finders.

Its object is to provide a line finder circuit arrangement wherein only three terminals per line are necessary, and wherein a line is made to test busy in the connector switches in which it appears, as well as calling in the finders in which it appears, immediately upon the initiation of a call in such line.

In accordance with this invention, each line is provided with a line and a cut-off relay, the cut-off relay being connected through a normal contact of the line relay with the multiple test terminals of such line in the finder and connector banks. The line relay is adapted upon its energization to start an idle line finder in motion, to disconnect the cut-off relay from the multiple test terminals and to connect thereto a stop relay which is connected to the other pole of the battery from that to which the cut-off relay is connected. The connection of this stop relay to the test multiples sets up a calling condition thereon in the finders and a busy condition thereon in the connectors. When the finder test brush reaches the calling line,

a circuit is closed including the stop relayreferred to, which in energizing opens the starting circuit to stop the finder upon the calling line terminals. The stop relay, in addition to opening the starting circuit, also initiates a circuit change which causes the deenergization of the line relay. The line relay, in falling back, restores the connection of the cut-off relay to the test multiples in order that it may be operated over a circuit leading through the finder to remove the control of the line relay from the calling line during conversation. The finder side switch. in the meantime, has operated to Specification of Letters Patent.

Patented Feb. 2'7, 1917;. Serial No. 73,218.

place a busy condition on the connecter test multiples in substitution of that leading through the stop relay.

Referring to the drawings, Figure 1 shows a finder circuit embodying the invention; and Fig. 2 shows a suitable connector circuit for operating therewith.

The invention will be more readily understood from a detailed description of the operations involved in setting up a connection.

Upon the removal of the receiver by the calling party at substation A, the following circuit is closed to energize line relay 10: free pole of battery, armature and back contact of relay 11, left winding of relay 10, left armature and back contact of cut-off relay 12, line conductor 13 through the telephonic apparatus at substation A, line conductor 14, right armature and back contact of relay 12, right winding of. relay 10 to ground. Relay 10 at its leftarmature and front contact closes the following circuit to energize a relay 15, which is common to the group of lines to which substation A belongs: free pole of battery, relay 15, conductor 16,- armature and backcontact of relay 17, conductor 18, armature and back contact of relay19, conductor 20, left armature and front contact of relay 10-,to ground. Assuming thelinefinder normally serving this line group to be in normal position, the group brush 21 on the finder brush shaft 42 will be in engagement with multiple contact 22 of the line group, in which position of the brush shaft a set of brushes, 23, 24, 25 thereon will. be in operative relation to multiples 26, 27, 28 of this particular line group. Under such assumption the following circuit is closed for the escapement magnet 29 of the side switchof the line finder in parallel with that traced for relay 15: free pole of battery, magnet 29, side switch arm 3 and" the following circuit is closed for the secrelay 15, conductor 16, left armature and front contact of relay 15, conductor 18, back contact'of relay 19, conductor to ground, at the left armature and front contact of relay 10. In position 2 of the side swltch,

- arm 4 connects battery to test brush of the finder through a resistance 31. a magnet now makes and breaks its circuit in the well-known manner to advance thebrushes 23, 24, 25, over the multiples 26, 27,

The

28. The energizationof the line relay 10 opens the connection ofbattery' through cut-0E relay 12 with finder multiple termi- 'nals 28 and connector multiples 34 and substitutes therefor ground through relay 19.

Consequently, when the brush 25 reaches the terminal 28 of the calling line, relay 19 becomes energized in the following circuit: free pole of battery, resistance 31, arm 4 and its second contact, brush 25, terminal 28, conductor 32, right armature and front contact of relay 10, relay 19 to ground. Relay 19 by attracting its armature opens the circuit just traced for the magnet 30, thus stopping the line finder upon the calling line terminals; In position 2 of the side switch, a

' circuit for escapement magnet 29 was closed in parallel with the circuit for magnet 30, as

follows: free pole of battery, magnet 29, am

" 3 and its second contact, conductor 33, arm

2 and its second contact to ground at the left armature and front contact of relay 10.

- 1 Consequently, when relay 19 energizes, it

opens this circuit also, whereupon escapement magnet 29 becomes denergized. The

escapement magnet 20 is constructed and arranged to move the side switch from position 2 to position 3 upon its deenergization. Relay 19 in attracting its armature, also energizes a slow relay 11 over the following circuit: free pole of battery, relay 11, armature and front contact of relay 19, conductor 20, left armature and front contact of relay 10 to ground. Relay 11, upon energization, opens the circuit of the line relay 10, which, in retracting its right armature, restores the connection of cut-0E relay 12 to test terminal 28. In position 3 of the side switch, arm 4 closes the following circuit for the cut-off relay 12 before slow relay 11 becomes denergized: free pole of battery, relay 12, right armature and back contact of relay 10, conductor 32, test terminal 28, brush 25, arm 4 and its third contact to ground. Relay 12, upon energizing, removes the control of relay 10 from the calling line. Arm 4 in moving into position 3 grounds the-test multiples 34 of the calling line in mamas the connectors in substitution of that through relay 19. Arm 2 in position 3 ex tends the starter wire 35 to the next idle finder. The retraction of the right armature of relay 15 restores the control of the starter wire 35 to the other groups. The relay 17 is slow acting, and by maintaining its armature attracted when the finder shown is being set by a call from another group, preventsa line from the group containing substation A from actuating-relay 15. The side switch arms 5 and 6 in position 3 extend the calling line to a first selector, the brushes 36, 37., 38, and terminals 39, 40, 41, only of which are shown since such structures are well-known in the art. During the operation of the finder, relay 17 at its right armature and front contact energizes a release relay 57 which maintains open the circuit of finder release magnet46. Relay 17 is slow acting, and does not retract its armature until after a slow relay at the first selector is energized and grounds conductor 58, in the well-known manner to hold up relay 57.

In case the line finder shown, which is theone apportioned tothis group, is busy, the starter wire 35 is extended by side switch arm 2 to the next idle finder. In order for such finder to reach a calling line in the group containing substation A, it is necessary that its brush shaft be given a primary movement to pick out the calling group. This will be .made clearfrom ,an explanation of the operations involved in causing the line findershown to connect with a line in another group. Assuming, therefore, that a call has been initiated in another group, this results in grounding conductor 35 incomingfroni such group, wh ch results in the closure of the followmg circuit: free pole of battery, magnet 20, 1ts armature and back contact, "side switch arms 1, 2 and their first contacts, conductor 35, slow relay 17, right armature and back contact of relay 15, conductor 35 to ground at the armature and front contact of the calling line relay. The magnet 20' by interrupting its circuit, steps the brush shaft 42 around in search of the callmg line group multiple 43, grounded by the operation of a relay of the calling group corresponding to relay 15. Consequently, when the brush 21 reaches such group contact, the following circuit is closed for escapement magnet 29: free pole of battery,

magnet 29, arm 3 and its first contact','brush' 21, multiple contact 43 of the calling group to ground. Escapement magnet 29 in energ1z 1ng, moves the side switch into position 2, 1n which positiona circuit is closed for stepping magnet 30 as follows: free pole of battery, magnet 30, its armature'and back contact, arms 1 and 2 and their second contacts to starter wire 35. A circuit in par-' allel to that just traced is also closed for magnet 29 by way of arm 3, its second contact and conductor 33. In position 2, arm

4 connects battery through resistance 31 to brush 25. As hereinbefore described, when the brush 25 reaches the test multiple 28 of the calling line, a relay of the calling group corresponding to relay 19 is energized to remove ground from the starter wire 35. This results in the deenergization of the escapement magnet 29, which releases the side switch'into position 3, and in the opening of the circuit of magnet 30, which stops the finder upon the calling line'terminals.

The first selector brushes 36, 37, 38 are then set under control of the sender S at the calling substation A in operative relation ture and back contact of relay 201, conductor 202, conductor 50, terminal 39, selector brush 36, conductor 53, arm 5 and its third contact, conductor 54, finder brush 23, terminal 26, conductor 13, through the telephonic apparatus at substation A, conductor 14, terminal 27, finder brush 24, conductor 55, arm 6 and its third contact, conductor.

56, brush 37, terminal 40, conductor 51, conductor 203, inner armature and back contact of relay 201, lower winding of relay 200 to ground. Relay 200 'at its armature and front contact closes a circuit to energize a slow relay 204. This relay at its left armature and'front contact, prepares a circuit for stepping magnet 206, and at its right armature and front contact grounds test conductor 205, leading back to the selector and finder to hold up relays bridged therefrom to maintain open the release circuits of such switches. The release relay 57 of the finder only is shown, as this arrangement is well known in the art.

The calling party now operates his sender in transmitting the tens digit of the called number. The sender inrestoring, interrupts the circuit of relay 200 in the well-known manner. Each time the armature of relay 200 closes its back contact, an impulse is sent to primary stepping magnet 206 of the connector. A. slow'relay 207 is included in this circuit, which relay,- unlike the magnet 206, does not respond to the short interruptions of the circuit. Relay 207, in attracting its armature, closes a circuit to energize escapement magnet 208 of the side switch, which is arranged to release the side switch upon its deenergization in the well-known manner. When the sender restores and maintains the relay 200 energized, the slow relay'207 becomes deenergized, and in retracting its armature causes the deenergization of theescapement magnet 208. This Inag-' net thereupon releases the side switch into position 2. In position 2, arm 209 of the side switch associates the secondary stepping magnet 210 with the back contact of the stepping relay 200. The sender is now operated to transmit the units digit of the wanted number. Each time the stepping relay 200 retracts its armature an impulse is transmitted to the secondary stepping magnet 210 in a circuit including the slow relay 207. This relay, as before, by attracting its armature, energizes the escapement magnet 208. In the circuit of escapement magnet 208 is a relay 211, which by attracting its armatures, opens the connection of conductors 212, 213 with connector brushes 214, 215 to prevent interference with existing calls. hen the sender restores and maintains the line relay 200 energized, slow relay 207, after an interval, becomes deenergized, causing the-denergization of es capement magnet 208 and relay 211, assuming the line selected to be idle. Side switch arm 245 in moving into engagement With its third contact grounds multiples 219 to cause the selected line to test busy. Side switch arm 209, in moving into position 3, prepares a circuit for a relay 220, which, when the constantly operating interrupter 221 reaches a metallic segment, becomes energized and connects the ringing generator 222 to the called line. The bell 23-1 of the called line is therefore intermittently rung to signal the wanted party. Upon the removal of the receiver-by such party, while the interrupter 221 is upon an insulated segment, supervisory relay 201 becomes energized over the following circuit: free pole of battery, right winding of relay 201, conductor 204, outer "armature and back contact of relay 220, lower armature and back contact of relay 211, brush 215, contact 218,

226, contact 21.7, brush 214, upper armature 'and back contact of relay 211, conductor 212, inner armature and back contact of relay 220, conductor 227, conductor 228, left winding of relay 201, to ground. This relay, by attracting its. outer armature, closes the following circuit to energize a relay 223: free pole of battery, arm 209, conductor 229,- relay 223, conductor 230, outer armature and front contact of relay 201, conductors 231, 232, off-normal contact 233 of the connector, to ground. This relay, by attracting itsleft armature, locks itself over conductor 235 independently of the armature and contact of relay 201. Relay 223 maintains open the circuit of relay 220, thus permanently cutting off the ringing current. Arms 248, 270 completethe talking circuit 1n position 3.

Talking current is fed to the calling substation A over the windings of relay 200, and to substation B over the windings of relay 201 in the well-known manner. Relay 201, upon its energization when the called party responds, reverses the direction of the current flow in the calling line, which may .operate a message register.

1 The release of the switches is controlled by the calling party, and occursupon the replacement of his receiver, which in deenergizing relay 200 closes the following circuit for the release magnet 236 of the connector: free pole of battery, magnet 236, off-normal contact 237, armatures and back contacts of relays 204, 200 to ground. This circuit is opened when the connector reaches its normal position by the opening of off-normal contact 237. The release magnet in energizing restores the side switch in the well-' known manner. Arm 209 of the side switch, in moving off its third contact, opens the locking circuit of relay 223. The connector apparatus is-now entirely restored. Relay 204 in retracting its armature removes ground from conductor 205, which results in the deenergization of the release relays of the selector and'finder. Relay 57 of the finder, in deenergizing, closes the circuit of, release magnet 46 of the finder to restore the same. When the finder shaft 42 reaches its normal position and opens off-normal spring 59, magnet 46 deenergizes.

Assume, however, that the selected line is busy as a called line when the connector brushes 214, 215, 216 are set thereon. After the last interruption in the line circuit caused by the sender, the relay 207, after an interval, becomes deenergized. A spring 239, controlled by the armature of this relay, is arranged to engage its contact 240 before said armature breaks contact with said spring. A busy line is one upon the test terminal 219 of which ground is present, as previously described. Consequently, when brush 216 engages such busy terminal, the following circuit is closed for the side switch escapement magnet 208 to maintain the same energized and hold the side switch in position 2: free pole of battery, escapement magnet 208, relay 211, conductor 242, spring 239, contact 240, relay 241, spring 243 and its contact, conductor 244, side switch arm 245, conductor 216 to grounded terminal 219. The side switch magnet 208 and the relay 241 are thereby maintained energized. Relay 241 at its outer left armature opens the circuit of secondary stepping magnet 210 to prevent the calling party from further operating the connector. At its inner left armature said relay connects lay, a

a busy back apparatus 245 to the calling line over the following circuit: busy back apparatus 245 conductor 246, said armature and its front contact, conductor 247, side switch arm 248 and its second contact to line conductor 203. The right armature, in engaging spring 243, closes a locking circuit for relay 241 independent of side switch arm 245 and grounded terminal 219. This circuit is as follows: free pole of battery, escapement magnet 208, relay 211, conductor 242, spring 239, contact 240, relay 241, spring 243, right armature of said relay, conductors 248, 232, off-normal contact 233 of the connector to ground. When the calling party restores his receiver to its switchhook, the release of the switches is effected as previously described in connection with a successful CalL' When the connector restores, the opening of off-normal contact 233 unlocks relay 241.

Assume now that the selected line is busy by reason of having initiated a call. The multiple terminals 34 thereof are then connected to ground through a relay corre* sponding to 19. When the connector is set upon such line, an energizing circuit for busy relay 241 is closed including relay 19, which latter relay, however, is not energized. From this point on, the operations are the same as those previously traced in describing the case where connection is made to a line which is busy by reason of having been connected to by. another connector.

What is claimed is: y

1. In a telephone exchange system, the combination with a calling telephone line, a line and a cut-off relay therefor, automatic finder switches, driving circuits therefor, multiple talking andtest terminals for said line in said finder switches, said cut-off relay being connected, to said test terminals through a normal contact of said line relay, means for closing the driving circuit of one of said finders upon the initiation of a call, means for preventing the operation of the cut-off relay of non-calling lines during the movement of said finder, a stop relay, said line relay being adapted when energized to disconnect the cut-off relay from said test terminals and connect thereto said stop recircuit adapted to energize said stop relay closed by said finder in arriving upon the calling line terminal, said stop relay thereupon opening the finder-driving circuit.

2. In a telephone exchange system, the combination with a calling telephone line, a line and a cut-off relay therefor, automatic finder switches, driving circuits for said finders, multiple talking terminals and a test terminal for said line in said switches, said cut-off relay being connected to the free pole of battery on the one side and to said test terminals on the other through a normal contact of said line relay, means for closing the driving circuit of one of said finders upon the energization of said line relay, a stop relay for said finders connected to the opposite pole of said battery from that to which the cut-off relay is connected, said line relay being adapted when energized upon the initiation of a call to disconnect said cut-off relay from said test terminals and connect thereto said stop relay, said test terminals being'ada ted to be connected to 10 my name this 19th day of January A. D. 15

CHARLES L. GOODRUM. I

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