US2039650A - Telephone system - Google Patents

Description

May 5, 1936.

J C. KELLY TELEPHONE SYSTEM Filed Jan. 23, 1935 2 Sheets-Sheet l lNl/EN TOR 4 J. c, KELLY A T TORNEY y 1936. J. c. KELLY 7 2,039,650

TELEPHONE SYSTEM Filed Jan. 25, 1955 2 Sheets-Sheet 2 l I HP F IH lq 0 w 9 $1 9 z M Q- l IIHII INVEN TOR J. C. KELLY A 7 ORNEY Patented May 5, 1936 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM York Application January 23, 1935, Serial No. 2,986

10 Claims.

This invention relates to telephone systems and particularly to remote control systems in which the establishing of connections between subscribers lines at a branch exchange is controlled by an operator at a main exchange.

It is an object of this invention to simplify the equipment used at the branch exchange for systems of this kind to respond to control over a trunk line from the main exchange.

Heretofore systems of this kind have been used in which, in response to a calling subscriber in a branch exchange removing his receiver from the switchhook, a line switch is operated to connect an idle trunk from a main exchange to the calling subscribers line and to signal an operator at the main exchange that a connection is desired. After having answered the call and received the called subscribers number the operator then dials the number back over the trunk and causes a selector switch associated with the trunk and the line switch to extend the connection between the calling line and the called line over these switches.

It is a feature of this invention to provide a single trunk line between a branch exchange and a main exchange and a single switch at the branch exchange for the purpose of controlling the establishing of connections between subscribers lines at the branch exchange and from subscribers lines at the branch exchange to subscribers lines at the main exchange by the aid of an operator at the main exchange.

Another feature of the invention is to employ the switch to connect a calling line in the branch exchange to the trunk and to employ the switch to connect the trunk to a called line in the branch exchange.

Another feature of the invention is to provide means whereby when a call is made to an operator at the main exchange the connection from the calling line to the trunk extends through contacts of the switch and whereby when a call is made to another subscribers line in the branch exchange the connection between the calling sub- 45 scribers line and the trunk is exchanged to extend directly from the calling line to the trunk independent of the switch, and the connection from the trunk to the called subscribers line extends through contacts of the switch.

5 It is another feature of the invention to provide means whereby the connection of a calling subscribers line to the trunk is effected in response to ringing current received over the call- I ing line from the calling subscribers ringing current generator.

It is another feature of the invention to provide means operative if the trunk is in use and a connection is desired by another subscriber at the branch exchange to signal the operator at the main exchange by a flashing signal and to signal 5" the connected calling subscriber and called subscriber and the operator by an audible signal.

The invention is illustrated in the accompanying drawings in which:

Fig. 1 shows the equipment at a branch ex- 10- change with a step-by-step switchused for controlling the establishing of connections between subscribers lines at the branch exchange and for subscribers lines at main exchange; while,

Fig. 2 shows a trunk circuit leading to main exchange and an operators position.

The establishing of a connection from one calling subscriber at the branch exchange to another calling subscriber at the same exchange will now be described. When the subscriber at l wants to establish a connection he first operates his hand generator which causes current to be transmitted over the tip and ring conductors through the upper winding of relay 2 and the upper inner armature and back contact. 2 to operate partially to open and close connections at armatures marked X. Thus this circuit through the upper Winding of relay 2 is opened while a holding circuit for relay 2 is closed from battery, third and second lower armatures of this relay through the lower winding to ground. A ground is removed from the marking contact corresponding to the calling line on bank B of switch SS, and a circuit is closed to operate the, relay 3 from battery through the upper winding of this. relay, contacts of relay 4, second upper armature and front contact of relay 2, to ground at the third upper armature and back contact of this relay. Normally relay 5 is operated over a circuit from battery through the winding of this. relay through back contacts of relay 3 over the tip and ring conductors of the trunk through the wind ngs of a normally operated relay IIJO to the charging battery [0| over contacts of this relay and relay I02. Relays 5 and I0!) are now released due to the operation of relay 3. The release of relay 5 performs no function at this time. Relay I!!!) in releasing closes a circuit for lamp I03 from battery contacts of jack I04, contacts of relays I00 and I02 through lamp I03 to. ground.

When now the operator at the main offlce answers by inserting a plug I05 of an answering cord into jack I06, relay I02 operates from bat- 55:

tery through the winding of this relay, contacts This causes relay 25 of the jack I06 to ground. This removes the windings of relay I00 from the ring conductor and connects battery to the tip and ring conductors for the completion of two circuits, one for relay 7 from battery, contacts of jack I04, lower winding of relay IIO, contacts of relay I 02, tip conductor, contacts of relay 3, a winding of repeating coil 6, winding of relay I to ground at contacts of relay 3, and another for relay 9 from battery, upper Winding of relay IIO, contacts of relay I02, resistance I01, contacts of the ringing key I08, ring conductor, contacts of relay I03, contacts of relay I0, lower right-hand winding of repeating coil 6, winding of relay 9, contacts of relay I to ground. Relay I in operating closes an obvious circuit for relay 8, and relay 9 in operating closes an obvious circuit for relay I2. Relay 8 in operating closes a holding circuit for relay 3 and a circuit for the operation of the stepping magnet I3 from battery, winding of this magnet and its self-interrupting contacts, contacts of relay I4, brush and first contact of bank B, upper inner armature and front contact of relay 8 to ground. This causes the stepping magnet to take one step and is then operated repeatedly from the ground on the succeeding contacts of its bank B of other subscribers lines until the terminal of the line I is reached where the ground has been removed by the line relay 2. The stepping magnet then stops operating for a moment to mark the calling line connection on this bank. Relay 2 is now fully operated from battery through the Winding of stepping magnet I3, its self-interrupting contacts, contacts of relay I4, brush of bank B, the marked contact, the lower inner armature and front contact of relay 2 and the lower winding to ground. The stepping magnet I3 does not operate in this circuit. The operation of relay 2 closes a circuit for the operation of relay I4 from battery, winding of this relay, contacts of relay 8, contacts of relay 2 to ground. Relay I4 in operating closes another circuit for stepping magnet I3 from battery, winding of this magnet and its self-interrupting contacts, second lower armature and front contact of relay I4, contacts of bank A and its brush to ground at whatever contact the brush of this bank is located. As the stepping magnet now operates, it moves the brush of bank A to the next contact, where the stepping magnet is again operated. This repeated operation of the stepping magnet is continued until the brush reaches the eleventh position on bank A where no ground is found for the stepping magnet which then stops. The calling subscribers tip and ring conductors are connected to the eleventh position of banks D and E and the brushes of these banks therefore connect the tip and ring conductors, over contacts of relays 4, and I2 through the left-hand windings of repeating coil 6. A connection is already completed through the right-hand windings of repeating coil 6 at the fourth lower armature and front contact of relay I2 for the tip and ring conductors overv the trunk so that a talking circuit is thereby prepared between the calling subscriber and the operator at the main oilice. It should be noted that there are two circuits for the windings of relay IIO, one extending from battery, upper winding of this relay, upper outer armature and front. contact of relay I02, resistance I 01, contacts of ringing key I08, the ring conductor of the trunk, contacts of relays 3 and I0, lower righthand winding of repeating coil 6, winding of relay 9 to the ground at relay I, while the other extends from battery, springs of jack I04, lower winding of relay IIO, contacts of relay I02, the tip conductors of the trunk, contacts of relay 3, upper right-hand winding of repeating coil 6, winding of relay I to ground at relay 3. These circuits are in opposite directions through the windings of relay I I0 so that this relay does not operate at this time.

When the operator finds that the desired subscribers line is a local subscriber in the branch exchange, that is, one connected in the same manner as subscriber I, she will connect her dial III through plug H2 in jack I04. While this opens the connection through the lower winding of relay IIO from the battery at the springs of jack I04, the connection for this winding is extended through the springs of jack I04, plug I I2; and pulsing contacts of dial III to battery sothat relay IIO will remain released. When now the operator actuates the dial I I I, a pulsing circuit is completed over the tip conductor for the pulsing relay I, the original circuit being extended from battery pulsing contacts and operated on normal contacts of the dial sleeve terminals of plug H2 and jack I 04, contacts of relay I02, tip

I conductor, contacts of relay 3, outer right-hand upper winding of repeating coil 6, winding of relay I to ground at contacts of relay 3. When the dial returns to normal, the pulsing contacts cause relay I to release for each impulse. On each release of relay I a circuit is completed for the stepping magnet I3 from battery, winding of this magnet, contacts of relay I4, lower armature and back contact of relay I. Relay 4 is also operated in this circuit and remains operated during pulsing. Stepping magnet I3 steps the brushes of switch SS to the terminals of the called line such as for example, if the subscriber at I was the called party, the brushes would step to the terminals to which this line is connected with its tip and ring conductors in banks D and E.

On completion of dialing the operator rings the called subscriber by operating the dialing key I08. This opens the tip and ring sides of the trunk and impresses ringing signals from the generator H3 on the ring side of the trunk connection. Relay H0 is prevented from operating during the ringing as a circuit is completed for the upper winding, contacts of relay I02, contacts of ringing key I08, through a resistance to ground. When the operator operated the ringing key, the connection for the ring side was only momentarily opened and this permitted the release of relay 9. Relay 9 in releasing causes the release of relay I2 which closes a circuit to the called subscriber at the inner lower armature and back contact over the ring conductor for the ringing current from the generator II 3 through contacts of relays 4 and I0 and brushes of banks D and E, back over the tip conductor, the upper inner armature and back contact of relay I2 to ground at the contacts of relay I4.

Ringing current from generator I I3 also passes through the right-hand lower winding of repeating coil 6, winding of relay 9 to ground at the contacts of relay I. Relay 9 does not operate under these circumstances sufliciently long to reoperate relay I2, as relay I2 is slow in operating. Ring back tone is afforded the calling subscriber through the condenser I6. When the called subscriber answers, and the operator releases her ringing key a talking connection is again established from the calling subscribers line to the called subscribers line as relays 9 and I2 are again operated.

When either party rings ofi by means 01' a hand generator, relay I09 operatesin. the trunk circuit over the tip. and ring conductors and locks up over its upper winding to ground at the closed contacts of jack we; Relay I09 closes a circuit for the disconnect lamp H4 and the operator removes her'plug I05 from jack 196, thus releasing relays Hi9 and E92. Relay 02 in releasing removes the windings of relay H from across the trunk, opens the tip connection and closes a circuit from the'charging battery IBI through the windings of relay Hill to the ring connection of the trunk. Relay 1 releases, causing the release of relays 8 and I 4. Relay l4 closes'a stepping circuit from ground. over the wipers of brush or bank A, contacts of relay l4, self-interrupting contacts and winding of the stepping magnet I3 to battery. Relay 4' is also operated in thiscircuit, the stepping magnet now returns the switch SS to normal and when the brush of bank A leaves the last contact, the stepping circuit is broken and the switch comes to rest in the home position. The remaining relays 3, 2 and 4 are released and charging is resumed over both sides of the trunk current passing through the winding of relay 5 which reoperates. Relay 2 will not reoperate even though the calling subscriber has the receiver oif the hook as this relay can only be originally operated through current produced by the hand generator at the calling subscribers set.

In making calls from the branch exchange to a subscriber in the main exchange the operation of the system is the same as described heretofore up to the point where the operator answers the call after which the operator extends the connection to the desired subscriber in any wellknown manner.

In making calls from the main exchange to a subscriber in the branch exchange the operator inserts plugs I05 into jack I06 thereby causing the operation of relay Hi2. This relay causes the release of relays IE0 and 5. Relay 5 in releasing closes a circuit for the operation of relay 3. This relay in operating closes the tip and ring of the trunk through to the repeating coil 6 to complete the operating circuit for relays-1' and 9 and the circuits function as described for a call originated by a branch exchange subscriber except that as no line relay is operated all marking contacts on the bank 2 will be grounded and the switch will rotate directly to the talking position on contact H and from then on respond to impulses from the operators dial as heretofore described to establish a connection to a desired called subscribers line. This subscriber will then be rung in the usual manner.

If the trunk is in use and another branch exchange subscriber should call, the line relay of this subscribers line will operate and lock up in the first step position in the usual manner but as the relay l2 will be operated due to the previous connection a circuit will be established from ground at the third upper armature and back contact and second upper armature and front contact of this calling subscribers line relay, the second lower armature and back contact of relay 4, second lower armature and front contact of relay I2, upper armature and back contact of relay 9, which at this time will be operated only to its first position, to battery through the winding of relay 2!), and also through the lower armature and. back contact of relay I0 through the winding of relay 2| to battery. Relays 2D and 2! will now operate. Relay 2!] in operating closes a circuit for the operation of relay 22 from battery' through one-half of the repeating coil 23,

lower winding of relay 22, lower armature and. front contact of relay 20, the other winding of retardation coil 23 to ground. Relay 22 operates and closes a parallel circuit'for its upper winding armature and front contact and as these two windings are opposed a buzzer action is set up and a tone is generated which is applied to the line through the upper armature and front contacts of relay 2%, resistance 24 and the lower right-hand winding of the repeating coil 5. This tone will be audible to the operator and to the subscribers talking on the established connection. Relay 2! which may be of the vibrating type closes a circuit for operating relay In. Relay lil in operating opens the ring side of the trunk at its upper armature and back contact and maintains a holding circuit for relay l2 so that this relay will not release when the trunk is opened. Relay ii! also opens a circuit for relay Zi which releases slowly. Relay 2! again closes a circuit for relay l6 and this cycle is repeated. ,The opening and closing of the ring side of the trunk causes the alternate operation and release of relay H39 in the trunk which thus causes the line lamp M4 to flash to indicate to the operator that a second party is waiting to make a call. Condenser 25 bridged across the onnections through the upper armature and back contact of relay [0 of the ring side of the trunk affords a by-pass for the tone while these contacts are open. The operator at the main office may remove the tone and stop the flashing by operating a tone and flash key IIB which short-circuits the resistance it? and thus allow relay 9 tooperate to its second step position and. open the operating circuit for reiays 26 and 2| causing them to restore. When the parties talking over the established connection ring off the operator withdraws her plug momentarily allowing the circuits to release as previously described and then plugs in again whereupon the switch SS will at once hunt for the waiting line. The circuits then function as before to establish a connection from this other calling subscriber to the operator at the main ofiiee and to establish a connection to another subscriber at the branch exchange or to extend the connection to subscribers at the main exchange as desired.

What is claimed is:

1. In a telephone system, subscribers lines, a trunk, an automatic switch, means for connecting a calling subscribers line through said switch to said trunk, means for connecting said calling subscribers line directly to said trunk independently of said switch connection and means for opening said switch connection and connecting a called subscribers line through said switch to said trunk.

2. In a telephone system, subscribers lines, a trunk, an automatic switch, means for actuating said switch to establish a connection between a calling subscribers line and the trunk and later to establish a connection between a called subscribers line and the trunk and means for establishing a connection between the calling subscribers line and the trunk independent of said switch and prior to the actuation of said switch for the establishing of the connections between the called subscribers line and the trunk.

3. In a telephone system, subscribers lines, a trunk, an automatic switch, means responsive to a signal from a calling subscribers line for connecting said line through said switch to said trunk, means responsive to a signal over said.

trunk for connecting said calling subscriber's line directly to the trunk independent of the switch connection, and means responsive to dialing impulses received over said trunk for actuating said switch to open the connection therethrough for the calling line and to establish a connection to a called subscribers line from the trunk.

4. In a telephone system, subscribers lines, a trunk, an automatic switch, means for establishing a connection from a calling line directly to said trunk and between a called line and said trunk through said switch'operative through the actuation of said switch once as a finder and. the second time asa connector.

5. In a telephone system, an exchange, an operators position, a signal at the operators position, subscribers lines terminating in said exchange, a trunk line terminating at one end in said exchange and at the other end in said operators position, a switch in said exchange, means responsive to a ringing signal from a calling subscribers telephone for establishing a connection through said switch to said trunk and to actuate the signal at the operators position, means responsive to the operator answering a call for disabling the signal and connecting the calling subscribers line to said trunk independent of said switch and means responsive to dialing impulses from said operators position received over said trunk for actuating said switch toconnect a called subscribers line to said trunk, means thereafter responsive to a ringing signal from another calling subscribers telephone for generating a ringing signal that is audible over the connection already established between a calling subscriber, a called subscriber and the operator.

6. In a telephone system, subscribers lines, a trunk, an automatic switch, a line relay for each subscribers line, means responsive to ringing signals from a calling subscribers telephone for partially operating the line relay of said calling subscribers line, for actuating said switch to a position identifying the calling subscribers line and for thereafter fully operating said line relay, means responsive to the full operation of said line relay for further actuating said switch to connect the calling subscribers line through contacts of said switch and through contacts of said relay to said trunk, means responsive to a signal incoming over said trunk for connecting said calling subscribers line to said trunk independent of the connection through contacts of the switch.

7. In a telephone system, subscribers lines, a trunk, an automatic switch, a line relay for each subscribers line, means responsive to ringing signals from a calling subscribers telephone for partially operating the line relay of said calling sub scribers line, for actuating said switch to a position identifying the calling subscribers line and. for thereafter fully operating said line relay, means responsive to the full operation of said line relay for further actuating said switch to connect the calling subscribers line through contacts of said switch and through contacts of said relay to said trunk, means responsive to a signal incoming over said trunk for connecting said calling line to said trunk indepndent of the connection through contacts of the switch, and means responsive to dial pulses incoming over said trunk for operating said switch still further to connect said trunk through contacts of the switch to a corresponding called subscriber's line.

8. In a telephone system, subscribers lines, a

trunk, an automatic switch, and means eflective through the operation of said switch in two independently and successively controlled movements for establishing a connection from a calling line directly to said trunk and between the trunk and a called line through contacts of said switch.

9. In a telephone system, subscribers lines, a trunk, an automatic switch, a line relay for each subscribers line, and means for establishing a connection between two subscribers lines with the trunk as a link and with a calling line connected to the trunk only through contacts of the line relay of said calling line and the called line connected to the trunk through contacts of the switch.

10. In a telephone system, a branch exchange, a main exchange, an operators position at the main exchange, an automatic switch in said branch exchange, a trunk with one end terminating in said switch at the branch exchange and terminating at the other end at said operators position at the main exchange, subscribers lines in said branch exchange terminating at two points in said switch, means responsive to a calling subscriber transmitting a ringing signal over his line for operating said switch, to connect said calling line to said trunk at one of said terminating points, means responsive when the operator seizes the trunk at the main exchange in answer to the connection of said trunk to a. calling subscribers line for connecting the calling subscribers line directly to the trunk independent of the connection at the switch, and means thereafter responsive to signal impulses transmitted from the operators position in the main exchange over the trunk for further operating said switch to connect a called subscribers line to the trunk at the other terminal point.

JOHN C. KELLY.

Images