US2324341A

US2324341A - Telephone system

Info

Publication number: US2324341A
Application number: US408911A
Authority: US
Inventors: Lee R Waller
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1941-08-30
Filing date: 1941-08-30
Publication date: 1943-07-13
Anticipated expiration: 1960-07-13

Description

July 13, 1943. wALLER 2,324,341

TELEPHONE SYSTEM Filed Aug. 30, 1941 I 2 Sheets-Sheet 1 $45 $4 H] VERT lNVE/VTO/P LRWALLER WEWH ATTORNEY L. R. WALLER 2,324,341

TELEPHONE SYSTEM Filed Aug. 30, 1941 2 Sheets-Sheet 2 lNI/ENTOR LR. WALLER A T TORNE Patented July 13, 1943 UNiTED STATES EATENT OFFICE.

or to Western Electric Company,

Incorporated,

New York, N. Y. a corporation of New York [application August 30, 1941, Serial No. 408,911 9 Claims. (01. 179-l8) This invention relates to telephone systems and particularly to those in which connections are established by automobile switches.

The object of the present invention is to simplify and enlarge the scope of signaling arrangements for use in telephone systems.

A feature of the present invention is an improvement in prior code ringing systems which consists in having a device connected to a subscribers station and selectabl by an automatic .7 switch, with means in the switch and the associated device arranged to form a circuit for creating the flow of alternating current responsive to the manipulation of the calling subscribers dial, for energizing said device in the called subscribers station connected thereto, thus providing a code ringing circuit which enables the calling subscriber to form any desired ringing code to attract the attention of a particular person within hearin called station bells.

A second and related feature of the present invention consists in providing two sets of terminals for a subscribers station in a switch bank, one set being connected directly to the subscribers station over one line channel and the second set being connected to said code ringing responsive device and thence over a second channel to said line and said subscribers station, either set of terminals being available having ringing equipment therein which is automatically responsiv to the selection of either set of terminals when the line is idle, which when connected to the terminals leading directly to the subscribers static-n causes the bell in said station to be intermittently sounded according to the interruption rate of said automatically responsive ringing equipment in said switching circuit, and which when connected to said second set, of terminals is immediately tripped and disconnected therefrom by the action of said device, causing responsive action in the switching circuit and the code ringing device to form a circuit which is responsive to alternating current created by the manipulation of the dial in the calling subscribers station for ringing the called subscribers station bell.

The foregoing and other features of the invention will be described more fully in the following detailed specification, which should be taken in :1

conjunction with the accompanying drawings, and the appended claims.

Referring to the drawings, scribers station A with dial representations of a Fig. 1 shows sub- 3, diagrammatic to ring the bell distance of the a for selection by a switch line finder LF, a first selector SI, and a second selector S2 of the usual type in step-by-step offices including their release magnets. The switching circuit for connector C is shown in detail arranged for the association of its brushes with switch bank terminals 45, 46 and 4'! or 48, 49 and 59.

Subscribers station E is shown in Fig. 2 connected directly to switchbank terminals 35, 46 and 41 and having the usual line and cut-off relays connected thereto. The subscribers station B is also shown in this figure connected to code ringing equipment responsive to the asso ciation of a connector switch with switch terminals 48, 49 and 50.

Fig. 3 shows a diagrammatic representation of subscribers station C having dial I29 associated therewith, line finder Hit, first selector 31, second selector I32 and connector I33 which may be the same as shown in Fig. 1. Connector bankterminals I31, 38 and 39 connect with code ringing responsive equipment for signaling a particular person. Subscribers station D is shown associated with a diagrammatic representation of switches for connection with the socalled answering terminals Hi4, I55 and 155 for connection through a relay in the code ringing equipment with the calling station.

The finder LF and selectors Si and S2 may be of any suitabl type, such as the step-by-step switch, the operation and release of which are well known.

A detailed description of the operation of the system will now be given, first, in connection with a call routed from station A to station B, for regular service via terminals 45, 38 and M, and secondly for a call from station A to station B via

terminals

38, 49 and 50 through the code signaling equipment connected to the latter terminals. A description of a code call for a hospital or factory building will also be given which employs the equipment shown in Fig. 3.

Let it be assumed that the subscriber at station A desires to establish a connection with the station E and that the connection has been eX- tended in the usual manner through line finder LF and selectors SI and S2 to the tip, ring and sleeve terminals of connector C. When this circuit is seized by the selector S2 a circuit is closed through the windings of relay 2| which may be traced from battery through the lower winding of relay 2|, normally closed lower contacts of relay 2!], ring terminals and brushes of selectors SI, S2, and the line finder LF, thence over line conductor l5 and through subscribers telephone A and dial 3, over conductor [5 and through tip terminals and brushes of line finder LF, and selectors SI and S2, normally closed upper contacts of relay 20 and upper winding of relay 2| to ground. Relay 2| operates which operates relay 22 through a circuit traceable from battery through the winding of relay 22 to ground on the contact of relay 2|. Relay 22 in operating connects ground on its contact 3 to the sleeve terminals and brushes of selectors SI, S2 and line finder LF', thereby holding in the op erated position the selectors and line finder and guarding connector C from other hunting selector circuits.

On the first break of the contacts of dial 3 for the purpose of dialing the tens digits of the called number, relay 2| releases and closes a circuit from battery through the windings of Vertical magnet 3| and relay 28, contact of the vertical ofi-normal contact assembly 32, contact 2 or relay 22 to ground on the contact of relay 2|. Relay 22 is slow to release and does not release during the momentary open periods of the front contact of relay 2|, while responding to the pulses of dial 3. Relay 28 and vertical magnet 3| are operated through the circuit hereinbefore retraced. As soon as the shaft of the connector switch is moved from its normal position on its first vertical step, the vertical off-normal springs 32 operate and transfer the operating circuit for relay 28 and vertical magnet 3| from contact to contact 2, thereby placing the windings of relay 28 and vertical magnet 3| in series through the make contact of relay 28, and contact 2 of the vertical olfnormal spring combination. This transfer is made Without interrupting the circuit, since the upper springs of the vertical off-normal spring combination are of the make-before-break type. After the contacts of dial 3 are closed again after the first break, relay 2| reoperates and again closes the circuit through the winding of relay 22, before this relay has had time to release, as hereinbefore explained. On the next open period of dial 3, relay 2| again releases and transmits a second ground pulse, through the circuit of relay 28 and vertical magnet 3|. Relay 28 is slow to release and remains locked 'up over the open periods of the back contacts of relay 2|. The second ground pulse causes the shaft of the switch to take another step upward. This action continues until all required pulses for the tens digits are transmitted by dial 3 and the connector brushes 42, 43 and 44 have reached the level containing the terminals of the line being called.

After the tens digit has been dialed and dial 3 is restored to normal, relay 2| remains operated, relay 28 releases, and the winding of vertical magnet 3| is deenergized. When relay 28 releases, a circuit is closed through rotary magnet 30 for rotary stepping and a circuit is closed for relay 26. These circuits may be traced from battery through the winding of rotary magnet 30, contact 6 of relay 25 and from battery through the winding of relay 26 to a junction point, thence through the upper contact of relay 21, back contact of relay 28, contact 2 of combination 32 to contact 2 of relay 22. On the first break of dial 3 for dialing the units digits of the called number, i, e., for rotary stepping, relay 2| releases and connects a ground impulse to contact 2 of relay 22 and over the rotary stepping circuit just traced. Relay 22 remains operated during dial pulses, as in the case of vertical stepping. In response to said first ground impulse rotary magnet 3| will operate and cause the switch brushes 42, 43 and 44 to rotate one step in a horizontal direction. Relay 26 operates to short-circuit the upper contacts of relay 21 to maintain the above circuit closed if relay 21 momentarily operates. Subsequent dial pulses cause rotary magnet 30 to step the switch around until the channel Ll or L|A of the called subscribers line is reached. Let it first be assumed that the pulses caused the connector brushes to be associated with channel Ll.

When dial I03 has restored to normal the circuit for relay 26 and the rotary magnet 36 is opened since relay 2| remains operated. Slow relay 26 does not release at once. Before connecting ringing current to this line a test is made to determine whether the line is busy or idle. If busy, ground will be found on the sleeve terminal 41, and will cause the operation of test relay 21 from battery through its winding, contact 2 of relay 25, contact 3 of slow-release relay 26, conductor 55, to ground on sleeve terminal 41 through brush 44. Relay 21 in operating opens the original circuit for rotary magnet 36 and when slow-release relay 26 finally releases 1e second circuit established for rotary magnet 36 is opened and a holding circuit is established for relay 21. Relay 21 in operating connects the secondary winding of busy tone transformer 46 through its contacts 3, to the ring conductor 56 which indicates to the calling subscriber A that the called line is busy. Relay 21 is locked up through a circuit traced from battery through the winding of relay 21, contact 2 of relay 25, contact 2 of relay 26 is released, contact 2 of relay 21 to ground on sleeve conductor 51. Under this condition the calling subscriber will disconnect, causing the release of relays 2| and 22, thereby closing a circuit from battery through the winding of release magnet 29, contact 3 of VON combination 32, contact 3 of relay 25, contact 2 of relay 22 and contact of relay 2|. to ground. Release magnet 29 is energized and causes the restoration of the connector switch to normal, including VON springs 32. Relay 21, which was locked to ground on sleeve conductor 51, releases since ground was removed by the opening of contact 3 of relay 22 when this relay released. The removal of ground from conductor 51 causes in the well-known manner the energization of relay magnets l0, H and i2 of the preceding switches and the consequent release of these switches.

Let it be assumed now that the line of the called subscriber station B is found idle when brushes 42, 43 and 44 encounter terminals 45, 46 and 41. Under this condition battery will be found by sleeve brush 44 on the terminal 41 connected through the winding of cut-off relay H9 and auxiliary lines busy relay 2. Under this condition relay 21 will not operate as hereinbefore described when the line Ll was found busy. After relay 26 has released upon the completion of rotary stepping, a circuit is closed for the operation of relay 25, which may be traced from aforesaid battery through the windings of relays H0 and 2, terminal 41, brush 44, through contact 2 of relay 26, lower winding of relay 25, contact 2 of relay 21 to ground on sleeve conductor 51. Relay 25 in operating looks through its upper winding and its contact 4 to ground on contact I of relay 22. Relay 25 also connects tip conductor 58, through its contact to ground on contacts of relay 24, opens the circuit of the winding of relay 21. by opening its contact 2,

connects ground from pick-up interrupter 33 through its contact 5, contact I of relay 23, contact 3 of relay 24 to battery through the winding of relay 23. Relay 23 operates and looks through its contact I to ground on contact 3 of relay 22. Relay 25 in operating also opens the lead to the rotary magnet 36 through its contacts 6, connects ring conductor 59 to ring conductor 60 through its contact 1', and joins sleeve conductor 5'! to sleeve conductor 35, thereby grounding said conductor for operating cut-off relay H and guard relay H2. Relay H9 opens the circult to line relay il l and relay H2 places a busy ground on sleeve terminal 53 to make the code pulsing equipment of this line busy to other calling lines.

When relay 23 operates it closes a circuit for ringing the station 3. This circuit is traced from source of ringing current 3 1, which may comprise an interrupter connected with an alternating current generator and with battery on different segments, through contact 2 of relay lower winding of relay 23, contact a of relay 2 over conductor contact I of'relay 25, conductor 58, through connector brush it and associated contact over line Li of subscriber B, contact c and associated brush 52, conductor 58, contact i of relay 25, to ground on contact I of relay 2 2. The ringer of station B is now actubut relay 24 does not operate until subscriber B answers by removing his receiver from the switchhook, thereby removing the ringer from the ringing current or silent interval battery circuit and connecting a low impedance bridge across the line. Ringing tone is intermittentiy sent back to the calling subscriber over conductor 5'5 during the periods when ringing current is connected with station B. The contacts of relay 2d are adjusted so that in operating a locking circuit is closed from battery through its upper winding and contact 2 to ground on contact i of relay 22 before the circuit through its lower winding is broken at either of its contacts i or i. The operation of relay 2e disconnects ringing current from subscribers station E. The locking circuit for relay 23 is also opened causing the release of the latter relay to disconnect the ringing source 3 1. In some instances the called subscriber such as the subscriber at station B may remove his receiver to make a call after a connector has been connected to his line, but before relay 23 has been operated by pick-up interrupter To guard this condition a circuit is provided to operate relay 2 1 before ringing current is applied to this called station. This circuit may be traced from battery through contact 2 of relay 23, lower winding of relay 24 and thence over the line conductors as traced through station 13 to ground on contact l of relay 24. Under this condition the locking circuit for relay 2 3 is established through its upper winding in the same manner as previously described.

The conversational circuit between the calling and called subscribers is completed by relay 24 by closing through the tip conductors on its contact I, and the ring conductors on its contact 4. Relay 24 in operating also completes the operating circuit for relay 20 through subscribers station 13, which may be traced from battery through the upper winding of relay 23, over the tip conductors of connector C and the line of station B, through station B including dial I23, ring conductors oi the line and of connector C to ground through the lower Winding of relay :0. Relay 29 in operating reverses the direction of current over the line of calling station A, thereby causing the operation of an associated line message register (not shown) in the well-known manner. After the aforesaid reversal, battery through the lower winding of relay 2| is connected by contact I of relay 2B of the tip conductor, and ground through the upper winding of relay 2| by contact 2 of relay to the ring conductor.

At the end of the conversation, when the calling subscriber disconnects, relays 2| and 22 release, removing ground from the upper locking windings of relays 24 and 25, which release. The release of relay 25 closes a circuit for operating release magnet 23, which may be traced from battery through the winding of magnet 29, contact 3 of VON combination 32, contact 3 of relay 25, contact 2 of relay 2! to ground. The operation of relay magnet 29 restores the connector switch to normal in the well-known manner. Also, the removal of ground from conductor 51 causes the operation of release magnets Ill, II and I2 and the immediate release of the preceding switches LF, SI and S2.

The system will now be described for code calling under the control of the calling subscriber who Wishes a particular person to answer the call at the called station. For this type of call, the connector C is directed to the second set of terminals 48, 49 and 5G to. which the called station 13 is available over channel LI-A as well as being available over terminals 45, 46 and 41 and. channel Ll. The connector C is controlled for connection to channel Ll-A by pulses in the same manner as for connection to channel Ll. If terminals 48, 49 and 50 are on the same horizontal level of the switch as terminals 45, 46 and 41, only the second series of connector switch pulses are different but if these sets of terminals are on different horizontal levels both series of connector switch pulses may be different for connection to channel Ll or Ll-A of subscribers station B.

Referring back to the description of the connector C it will be remembered that a test of the line is made when brushes 42, G3 and 44 are connected to the terminals of this line. If a busy ground is encountered on the sleeve terminal, a busy tone is transmitted to the calling subscriber and if battery is encountered on the sleeve terminal the line is idle and may be seized by the connector. The same action in this respect ocours in the connector circuit when brushes 42, .3 and 44 are connected to terminals 48, 49 and so as described when these connector brushes were connected to terminals 45, 4S and 47. Let it be assumed that the line of the called subscribers station E is found idle when brushes 42, 43 and M encounter the code signaling equipment or auxiliary line circuit connected to line terminals 48, 49 and 59 and that circuits have been established in the connector for seizing this line by way of its auxiliary line channel. A circuit is thus established for relay H3 from battery through its winding, back contact of relay H2, sleeve terminal 50, contact 8 of relay 25, operated, to ground on contact 3 of relay 22 which is operated. The operation of relay H3 establishes a circuit for operating cut-off relay HE from battery through its winding, contact I of relay H3 to ground. This also places a busy ground on sleeve line terminal 4?.

Relay 23 of the connector circuit operates as previously described to ground on pick-up interrupter 33 and locks to ground on contact 3 of 22, and the contact of relay relay 22. This connects ringing current and battery from different segments of an interrupter 34, through contact 2 of relay 23, lower winding of relay 24, contact 4 of relay 24, conductor 60, contact 1 of relay 25, conductor 59, connector brush 43, contact 49, contact 2 of relay II3 to ground on contact 2 of relay II5. An automatically responsive code ringing device may be substituted for the interrupter 34. Relay 24 operates in the circuit traced and disconnects ringing current which in this type of connection does not actuate the bell in subscribers station B. Relay 24 looks through its upper winding to ground on contact I of relay 22 and opens the locking circuit for relay 23 which releases. The release of relay 23 opens the circuit to ringing current source 34. A circuit is now established for relay I I to open the ground connection used for tripping the ringing current. This circuit may be traced from ground through the Winding of relay II5, tip terminal 48, brush 42, contact I of relay 25, contact I of relay 24, upper winding of relay to battery. Relay II5 Operates in the circuit traced but relay 20 does not operate due to the high resistance of relay II5. Relay II5 locks through its contact I, contact 5 of relay I I3, resistance I I1 to battery.

The circuit is now prepared to receive low frequency ringing current formed into any desired code by manipulation of the dial in the calling subscribers station A. At this time a circuit extends from battery through the lower winding of relay 2|, contact 2 of relay 20, thence over the ring side of the line and through the calling subscriber station including dial 3, tip side of the line, contact I of relay 29, upper winding of relay 2| to ground. A second circuit extends from battery through the upper Winding of relay 22 to the tip conductor 62 where one branch eX- tends through condenser 35 to the tip of the line and to ground, through the upper winding of relay 2I and another branch extends through contacts I of relays 24 and 25, brush 42, terminal 48, winding of relay II4, condenser I29, terminal 49, brush 43, contact 1 of relay 25, contact 4 of relay 24, conductor 56, where one branch extends through the lower winding of relay 20 to ground and another branch through condenser 36 to the ring of the calling line and to battery through the lower winding of relay 2|. Thus a circuit is formed for creating low frequency alternating current from interruptions of dial 3 corresponding-to the speed of the dial. Relay I I4 is designed to operate on this alternating current according to any code desired by the calling subscriber.

The operation of relay II4 energizes relay Hi5 over an obvious circuit and the operation of relay IIB connects the ringing current source I24, through contacts I and 2 to leads I and I26 connected to the line leading to subscribers station B for ringing the bell in this station. A code signal may be given to difierentiate from the machine ringing transmitted over channel LI and a code may be formed to call a particular person to the telephone in station B. During each ringing period relay I21 is operated from ground on contact 3 of relay II6. Relay I21 remains operated momentarily after relay H6 has released in order to drain the subscribers station ringer and line of any charge through resistances II 8 and I I9 to battery and ground after each code ringing period.

The removal of the receiver in station B completes a circuit for connector relay 29. This circuit may be traced from battery through the upper winding of relay 20, thence over conductors 62 and 58, brush 42, terminal 48, contact 4 of relay II3, contact I of relay I21, contact I of relay I I6, conductor I25, station B including dial I23, conductor I26, contact 2 of relay II6, contact 2 of relay 2I1, contact 3 of relay II3, terminal 49, brush 43, conductors 59, 66 and 56, lower winding of relay 20 to ground. Relay 2 0 in operating reverses the direction of current over its contacts and the calling line thereby causing the operation of a message register (not shown) in the well-known manner.

At the end of conversation, when the calling party A disconnects, relays 2| and 22 release, removing ground from the upper locking windings of relays 24 and 25 which release. The release of relay 25 closes a circuit for operating release magnet 29 as previously described causing the release of the connector and the preceding switches LF, SI and S2.

The code dialing system using the dial in the calling subscribers station for creating alternating current in a connector circuit and associated responsive circuit just described is also herein applied to a code signaling arrangement for hospitals and factories as shown in Fig. 3. For a description of this let it be assumed that the subscriber in station 0 has energized the line finder I39, first selector I3I, second selector I 32 and connector I33 by pulses from dial I29 in the same manner as herein described for the operation of the same switching equipment, Fig. l. The connector brushe I34, I35 and I36 are thus connected with terminals I31, I38 and I39 on a particular switch level leading to the code responsive equipment for ringing bells in different locations of a hospital or factory building. Let it also be assumed that the person wanted is not available in his ofiice. Since the connector I33 is the same as the connector C shown in Fig. 1, a busy or idle test of the line is made and if the line is idle a circuit is established for relay I43 from battery through its winding, terminal I39, brush I36 to ground on contact 3 of a relay the same as relay 22. This establishes a circuit for tripping off the ringing current in the manner previously described by connecting ground from contact 2 of relay I44 through contact 2 of relay I43, terminal I38, brush I35 to th ring conductor of the connector which operates relay 24 and releases relay 23. The operation of relay 24 establishes a circuit for relay I44 to remove the above ground circuit from the ring conductor. The circuit for relay I44 may be traced from ground through its winding and contact I, terminal I31, brush I34 to battery through the wind ing of relay 29. Relay I44 looks through its contact I, contact 4 of relay I43, resistance I48 to battery. Relay 20 does not operate in the circuit traced because of the high resistance of relay I44.

A code ringing circuit has now been set up in- .cluding the connector circuit and relay MI and condenser I42 which is the same as previously described for the operation of relay H4, and by the manipulation of the dial the subscriber at station C may send a prearranged or private code to operate a number of bells the same as bells I45 in different locations of a hospital or factory building. The operation of the dial thus creates low frequency alternating current in the connector circuit and the circuit of relay I4I which actuates the latter relay. This operation of relay I4I establishes an obvious energizing circuit for relay I45 which connects ringing current source I10 with a number of bells such as I46. Relay I41 is operated by relay I45 to drain the signal bells and line of any charge after each code ringing period.

A person hearing his code on the bells may respond from the nearest subscribers set by dialing a certain number known as the answering number, with the result that an automatic switch connects with the code signaling equipment at the so-called answering set of terminals as fully described in Patent 1,585,909 to M. L. Nelson, May 25, 1926. This connects brushes II, I58 and I59 with switchbank terminals I55, I55 and H55 to complete the connection between the calling and the called subscribers stations. Brush I59 having ground connected thereto establishes a circuit for relay I46 which completes the conversational connection and causes the reversal of the battery connection over the callin line by the operation of relay 28. The circuit for relay 2 3 constitutes part of the transmission circuit and may be traced from battery and ground through the windings of rela 2% over the tip and ring conductors to brushes I34 and I35, through contacts 5 and 3 of relay H53, contacts I and 2 of relay I46 and retardation coil lEfi. A similar transmission and signaling circuit extends through retardation coil 55 I.

At the end of conversation, connector 33 is released by restoring the receiver in the calling station as previously described which also restores the first and second selectors ISI and I32 and the line finder L38. The release of the connector l33 releases relay Hi3 which causes the release of relay I44. Restoring the receiver in the called station likewise restores the switches associated therewith which restores relay I40 and the circuit may again be used for a code ringing signal.

What is claimed is:

1. In an automatic switching telephone office, subscribers stations having dials therein connected by lines to said ofiice, a switching system connected to said lines including connector switches, means including switching and transmission circuits in said connector switches for se lecting switchbank line terminals responsive to dial pulses from a calling subscriber station, a code signaling circuit for a subscriber station connected to said switchbanh line terminals, means in said connector circuit and said code signaling circuit responsive to the selection of terminals connected to said code signaling circuit to form a circuit in said connector and code signaling circuit for causing theflow of alternating current responsive to further manipulation of the dial in the calling subscribers station, and means in said code signaling circuit responsive to said flow of alternating current for ringing the bell in the associated subscribers station in any code created by the operations of said dial.

2. In an automatic switching telephone cfiice, subscribers stations having dial therein connected by lines to said office, a switching system connected to said lines including connector switches, means including switching and transmission circm'ts in said connector switches for selecting switchbank line terminals responsive to dial pulses from a calling subscriber station, a code signaling circuit for a subscriber station connected to said switchbank line terminals, means in said connector circuit and said code signaling circuit when associated together for forming a circuit in said connector and the selected code signaling circuit for creating low frequency alternating current responsive to further manipulation of the dial, said frequency corresponding to the speed of said dial and means in said code signaling circuit operatively responsive to said low frequency alternating current for connecting a higher frequency alternating current source with said line for ringing the subscribers station bell.

3 In an automatic switching telephone office, subscribers stations having dials therein connected by lines to said office, a switching system connected to said lines including connector switches having automatic ringing means therein, means in said connector switches for selecting switchbank line terminal responsive to dial pulses from a calling subscriber station, code signalin circuits, a subscriber station having one channel of its line connected directly to one set of switchbank terminals and a second channel of its line connected to a code signaling circuit which is connected to a second set of switchbank terminals, said station being selectable over the direct channel for automatically controlled ringing of the subscribers station bell and the second channel for code ringing under the control of the calling subscriber, means in a code signaling circuit and a connector switch when associated therewith for forming a circuit to cause the flow of alternating current responsive to further manipulation of the dial in the calling subscribers station and means in said code signalin circuit responsive to said flow of alternating current for ringing the bell in the associated subscribers station in a code created by the operations of the dial in the calling subscribers station.

4. In an automatic switching telephone ofiice, subscribers stations having dials therein connected by lines to said oflice, a switching system connected to said lines including connector switches, means in said connector switches for selecting switchbank line terminals responsive to dial pulses from a calling subscriber station, code signaling circuits, a subscribers station having one channel of its line connected directly to one set of switchbank terminals and a second channel of its line connected to a code signaling circuit which is connected to a second set of switchbank terminals, said station being available over either channel, automatic ringing means in said connector circuits for ringing the subscribers station bell in a predetermined order responsive to the association of said connector with the channel leading directly to said subscribers station, means in said code signaling circuit responsive to the association of a connector circuit with. said second channel for cooperating with said connector circuit to disconnect said automatic ringing and form a circuit for causing the flow of alternating current responsive to further manipulation of the dial in the calling subscribers station in any code created by said calling subscriber and means in said code signaling circuit responsive to said flow of alternating current for ringing the bell in said subscribers station in an order as controlled by the operations of the calling subscribers station dial.

5. In an automatic switching telephone ofiice, subscribers stations having dials therein connected by lines to said ofiice, a switching system connected to said lines including connector switches, means in said connector switches for se lecting switchbank line terminals responsive to dial pulses from a calling subscriber station, code signaling circuits, a subscribers station having one channel of its line connected directly to one set of switchbank terminals and a second channel of its line connected to a code signaling circuit which is connected to a second set of switchbank terminals, said station being available over either channel, automatic ringing means in said connector circuits for ringing the subscribers station bell in a predetermined order responsive to the association of a connector switch with the channel leading directly to said subscribers station, a relay in said code signaling circuit operatively responsive to the association of a connector with said second channel to operate the connector means for disconnecting said automatic ringing, means responsive to the operation of said connector means to alter said code signaling circuit by the operation of a second relay to form with said connector circuit, a circuit for creating alternating current responsive to further manipulation of the dial, said alternating current being of low frequency corresponding to the speed of said dial, and a relay in said code signaling circuit operatively responsive to said low frequency alternating current for connecting a higher frequency alternating current source with said line for ringing the subscribers station bell in an order as controlled by the operations of said dial.

6. In an automatic switching telephone oflice, subscribers stations having dials therein connected by lines to said ofiice, a switching system connected to said lines including connector switches having switching and transmission circuits, means in said connector switches for selecting switchbank line terminals responsive to dial pulses from a calling subscriber station, a code signaling circuit connected to said switchbank line terminals and having a plurality of bells connected thereto, means responsive to the selection of said code signaling circuit by a connector for operating both the code signaling circuit and connector circuit to form a circuit in said connector and code signaling circuits for causing the flow of alternating current responsive to further manipulation of the dial in the calling subscribers station in any code created by said manipulation of said dial, means in said code signaling circuit responsive to the flow of said alternating current for ringing said plurality of bells according to the code created, an answering subscriber station having a dial and switches connected thereto, means responsive to the ma nipulation of said latter dial for operating said latter switches for effecting connection with said code signaling circuit, and means in said code signaling circuit operatively responsive to said connection for connecting said answering subscribers station with said calling line through said connector switch.

7. In an automatic switching telephone ofiice, subscribers stations having dials therein connected by lines to said oilice, selectors and connector switches having circuits and equipment operably responsive to the manipulation of the dial in a calling subscribers station for associating the connector switch brushes with connector switch terminals to select a called line, auxiliary equipment individual to lines connected to connector switch terminals, means in said auxiliary equipment responsive to the selection thereof by a connector for operating the connector circuit to associate the calling line with said auxiliary equipment, means in the connector circuit and said auxiliary equipment responsive to said latter action for creating a signaling circuit responsive to further manipulation of the dial for operating said auxiliary line equipment in code of any character as organized by the calling subscriber and means in said auxiliary equipment responsive to said letter operations for signaling the called subscribers station in an equivalent code.

8. In an automatic switching telephone ofiice, subscribers stations having dials therein connected by lines to said ofiice, selectors and connectors operably responsive to the manipulation of the dial in a calling subscribers station for associating the connector switch brushes with connector switch terminals of the called line, ringing equipment in said connector automatically operated by the selection of the called station line for associating a ringing current circuit therewith for ringing the bell in said called station, tripping equipment including a relay in said connector to open the ringing current circuit when the resistance of the line is lowered such as by the removal of the receiver from the switchhook, lines having auxiliary equipment therein connected to the connector switch terminals, means in said auxiliary line equipment for operating said relay in the connector to trip on said connector automatic ringing circuit and connect the calling subscribers station with alternating current responsive means in said auxiliary equipment, which arranges a circuit formation in the connector and the auxiliary equipment, providing means to create alternating current responsive to further manipulation of the dial in the calling subscribers station for operating said alternating current responsive means and means operated by said alternating current responsive means for signaling the called subscribers station.

9. In an automatic switching telephone ofiice, subscribers stations having dials therein connected by lines to said ofiice, selectors and connectors operably responsive to the manipulation of the dial in a calling subscribers station for connecting said station to a called station by associating the connector switch brushes with switch terminals of the called line, ringing equipment in said connector automatically operated by the selection of the called station line for associating a ringing current circuit therewith for ringing the bell in said call station, tripping equipment including a relay in said connector to open the ringing current circuit when the resistance of the line is lowered such as by the removal of the receiver from the switchhook, lines having auxiliary equipment therein connected to the connector switch terminals, means in said auxiliary line equipment for operating said relay in the connector to trip off said connector automatic ringing circuit and connect the calling subscribers station with alternating current responsive means in said auxiliary equipment, which arranges a circuit formation in the connector and the auxiliary equipment, providing means to create alternating current responsive to further manipulation of the dial in the calling subscribers station for operating said alternating current responsive means, means operated by said alternating current responsive means for signaling the called subscribers station by associating another ringing current source therewith and means in said auxiliary equipment responsive to the removal of the receiver in the called station to trip off said latter ringing current source and connect said called subscribers station with said calling subscribers station.

LEE R. WALLER.