US1212494A - Telephone-exchange system. - Google Patents

Description

L. H. JOHNSON TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAY 26. 1916.

Patented Jan. 16, 1917.

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ENTTED ETATEB; PATENT @EETQE.

LEWIS H. JOHNSON, OF BLOOMFIELD, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEVV' YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented an. is, 1.917.

Application filed May 26, 1916. Serial No. 99,978.

To all whom it may concern:

Be it known that I, LEWIs H. JOHNSON, a citizen of the United States, residing at Bloomfield, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone-Ex change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to such systems of the centralenergy type in which an operators telephone set is automatically connected to and disconnected from a calling telephone line.

The object of this invention is the provision of means for increasing the eficiency of the operators of a telephone exchange and for facilitating the completing of connections between subscribers.

In accordance with this invention, a telephone exchange system, in which the operators telephone set is automatically connected to a calling telephone line upon the connection of a link circuit therewith, is provided with circuits and apparatus, so organized that, while the operators telephone set is connected to one calling telephone line, it can not be connected to any other calling line, but a second connection may be.pre pared during the existence of the first so that upon the disconnection of the operators telephone set from the first calling line, it will be immediately connected to the calling line forming a part of the prepared connection.

This invention is an improvement on that disclosed in the application of Henry P. Clausen, Ser. No. 59,972, filed November 6, 1915, in that less apparatus is required for accomplishing the desired result.

More specifically, this invention contemplates a telephone exchange system in which there are link circuits for interconnecting the lines and a relay associated with each link circuit for automatically connecting the operators telephone set with the talking strands thereof when connected with a call ing telephone line. Each link circuit is also provided with a second relay, the opera tion of any one of the listening relays conditioning the'second relay of all other link circuits for operation, the second relay of any of the other cord circuits being then operated upon the connection of its associated link circuit with, annther calling. line- The operation of this secondrelay. of another link circuit prevents the operation of the listening relay thereof, thereby preventrupter mechanism in circuit with the signaling device to furnish a signal to the operator.

This invention is illustrated in the accompanying drawing in which there are shown ordinary subscribers lines A, B, C and D (subscribers lines B, C, and D being indicated merely by the answering jacks thereof), and two cord circuits E and F for interconnecting the subscribers lines. The appartus of each cord circuit is exactly alike, and the same reference characters will be used in each to indicate the same apparatus.

Assuming that subscriber A wishes to converse with subscriber B, A will signal the central office in the usual manner, whereupon the operator willinsert the answering plug of the cord circuit E into the jack associated with As line, causing the operation of sleeve relay 5 and supervisory relay 6. The operation of supervisory relay 6 causes the operation of listening relay 7 over a circuit from battery through contact 8 of relay 9, lower winding of relay 7, left-hand normal contact of relay 10, alternate contact of supervisory relay 6 and supervisory lamp 11 to ground. The operation of the listening relay 7 connects an operators telephone set 12 t0 the talking strands of cord circuit E,

- and by the engagement of its lower armature with contact 13, connects battery to one terminal of the right-hand winding of relay 10 of the cord circuit F by way of contact 13 of relay 7 (cord circuit E), common conductor 14, contact 15 of relay 7 (cord circuit F), right-hand normal contact of relay 9 to one terminal of the-right-hand winding of relay 10 of cord circuit F, thereby conditioning this relay for operation. It will be, understood that the relay 10 in each of the cord circuits of this position other than the cord circuit E, will be conditioned for operation by the operation of the listening relay 7 of the cord circuit E. After ascertaining that subscriber A wishesto be connected to the 1s f. ubscriber. Ba hefire atar nser s ha calling plug into the jack of Bs line, causing the operation of relay 9, which opens the normal contacts thereof and closes the lefthand alternate contact. The opening of contact 8 of relay 9 removes the short circuit from the middle winding of relay 7, whereupon this relay receives current from battery through the middle and lower windings, normal left-hand contact of relay 10, alternate contact of supervisory relay 6 and supervisory lamp 11. The middle and lower windings of listening relay 7 are connected in series opposing, so that when the circuitis completed through both of these windings, the magnetizing eflect produced by one is neutralized by that of the other, so that the relay releases. Upon the release thereof, battery is removed from the common conductor 14. The closure of the left-hand alternate contact of relay 9 causes supervisory lamp 21 to light. The operator may now actuate ringing key 22 to send ringing current out over Bs line to operate the call bell thereat. Subscriber B, in responding, removes the receiver from the switch hook, causing the operation of supervisory relay 23 to elface supervisory lamp 21. Upon the completion of the conversation, subscribers A and B restore the receivers to the switch hooks, causing the supervisory lamps 11 and 21 to light to furnish disconnect signals. The operator then withdraws the plugs from the jacks, whereupon all apparatus returns to normal.

Suppose that while the operator was busy completing connections between subscribers A and B, but before the calling plug of cord circuit E was inserted into the jack of Bs line, subscriber C had initiated a call. The operator could take up this call by inserting the answering plug of cord circuit F into the jack of Us line, thereby causing the operation of sleeve relay 5. The operation of this relay causes the operation of relay 10 over a circuit from battery, through contact 13 of relay 7 (in cord circuit E), common conductor 14-, contact 15 of relay 7 (in cord circuit 1*), right-hand normal contact of re lay 9, right-hand winding of relay 10 and contact of relay 5 to ground. Supervisory relay 6 of cord circuit F will also have operated upon the insertion of the calling plug into the jack of Us line, so that with relays 6 and 10 operated, supervisory lamp 11 is caused to flash intermittently, due to inter rupter 25 being in circuit with the lamp, this circuit being from battery through the interrupter 25, left-hand alternate contact of relay 10, alternate contact of supervisory relay 6 and supervisory lamp 11 to ground. The operation of relay 10 opens its left-hand normal contact which is in circuit with the lower and operating winding of listening relay 7 (of cord circuit F), so that this relay is prevented from operating, although the alternate contact of supervisory relay 6, which is in the operating circuit for this listening relay, is closed. The supervisory lamp 11 continues to flash until subscriber C has restored his receiver to the switch hook, or until the operator has inserted the calling plug of cord circuit E into the jack of BS line. The insertion of the calling plug of this cord circuit E into the jack of HS line causes the operation of sleeve relay 9, which opens its right-hand normal contact, permitting relay 7 of cord circuit E to release. The release of this relay removes battery from the right-hand winding of relay 10 of cord circuit F, which releases, closing its lefthand normal contact, whereupon listening relay 7 of cord circuit 13 operates over a circuit similar to that traced for relay 7 of cord circuit E. The release of relay 10 also removes the interrupter 25 from the circuit of the supervisory lamp 11, which thereupon ceases to flash. The connections between subscribers C and D may now be completed in the same manner as hereinbefore described in connection with the completion of connec-.

tions between subscribers lines A and 13.

Suppose that the operator, upon receiving the disconnect signals from subscribers A and B, does'not immediately withdraw the plugs from the jacks, and suppose further that after having restored the receivers to the switch hooks, subscriber A wishes to initiate another call. The removing of the receiver from the switch hook will cause supervisory lamp 11 of cord circuit E to flash intermittently. The manner in which this is accomplished will now be described. Upon restoring the receiver to the switch hook, the supervisory lamp 11 was lighted to furnish a disconnect signal, and relay 10 was operated over a circuit from battery through the left-hand alternate contact of relay 9, normal contact of supervisory relay 7 ceiver is removed from the switch hook by subscriber A, the operation of supervisory relay 6 completes a circuit from battery through the interrupter 25 and supervisory lamp 11. The operator, upon observing this flashing signal, actuates key 30 to release relay 10 and remove the interrupter from circuit relation with supervisory lamp 11, and causes the operation of listening relay 7 to connect the operators telephone set 12 to the talking strands of cord circuit E. The operating circuit for relay 7 may be traced from battery through the left-hand alternate contact of relay 9, alternate contact of key 30 and the upper winding of relay 7 to ground. After ascertaining subscriber As wants, the operator may restore key 30 to normal position, withdraw the calling plug from Bs line and complete'connection from As line to any other desired.

That is claimed is:

1. In a telephone exchange system, subscribers lines terminating at a central oflice, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit therewith, and a second relay conditioned for operation upon the operation of the listening relay of a busy link circuit and operated upon the connection of another link circuit with another line to prevent the actuation of the listening relay thereof.

2. In a telephone exchange system, subscribers lines terminating at a central office, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit therewith, and a second relay conditioned for op eration upon the actuation of the listening relay of a busy link circuit and operated upon the connection of another link circuit with another line to open the circuit of and prevent the actuation of the listening relay thereof.

3. In a telephone exchange system, subscribers lines terminating at a central office, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit therewith, a second relay for each link circuit, and a circuit for each second relay open at two points, the operation of the listening relay of a busy link circuit closing one break in the circuit of the second relay of another link circuit, the second break thereof being closed upon the connection of said another link circuit with another line to actuate said second relay thereof and prevent the operation of the listening relay thereof.

a. In a telephone exchange system, subscribers lines terminating at a central ofiice, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit therewith, and a second relay for each link circuit, the second relay of another link circuit being conditioned for operation upon the operation of the listening relay of a busy link circuit and operating upon the connection of said another link circuit with another line to prevent the operation of the listening relay thereof.

5. In a telephone exchange system, subscribers lines terminating at a central office, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit therewith, a second relay conditioned for operation upon the operation of the listening relay of a busy link circuit and operated upon the connection of another link circuit with another line, a signaling device associated with said another link circuit, and interrupter mechanism brought into circuit with the signaling device upon the operation of said second relay.

6. In a telephone exchange system, subscribers lines terminating at a central office, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit there with, a second relay conditioned for operation upon the operation of the listening relay of a busy link circuit and operated upon the connection of another link circuit with another line, a signaling device associated with said another link circuit, interrupter mechanism brought into circuit with the signaling device upon the operation of said second relay, and means for deenergizing the listening relay of said busy link circuit and the second relay upon the connection of the busy link circuit with a called line.

7. In a telephone exchange system, subscribers lines terminating at a central oiiice, link circuits for interconnecting the lines, an operators telephone set, a listening relay for each link circuit operating upon the connection thereof with a calling line to include the operators telephone set in circuit therewith, a second relay conditioned for operation upon the operation of the listening relay of a busy link circuit and operated upon the connection of another link circuit with another line to prevent the actuation of the listening relay thereof, and means operating upon connection of the said busy link circuit with a called line for causing the deenergization of the listening relay thereof and the second relay to actuate the listening relay of said another link circuit.

In witness whereof, I hereunto subscribe my name this 24th day of May, A. DJ 1916.

LEWIS I-I. JOHNSON.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. O.

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