US1345348A - Telephone-exchange system - Google Patents

Description

H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED IUNEYZS, I917.

1,3453348. t t d uly 6, 1920.

/n ven for: Henry F C/ausen UNITED STATES PATENT OFFICE.

HENRY I. GLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORA- TION OF NEW YORK.

Specification 0! Letters Patent.

TELEPHONE-EXCHANGE SYSTEM;

' Patented July 6, 1920.

Application filed .Tune 25, 1917. Serial No. 176,808.

trunk circuits between originating (A) or terminating (B) boards for interconnecting telephone lines terminating at the different boards, which may be in the same or different central offices.

In such systems it is frequently desirable that the connection to the wanted line including the trunk circuit and a link circuit be built up and that the application of ringing current to the wanted line be delayed until such time as the operator at the A board determines. This is particularly desirable in working connections between local and toll lines, when it is economical to hold the local line while building up the connection between the link circuit and an expensive toll line. In systems of this character, it is usual for the operator at the A board to have complete charge of the supervision over such connections, so the connection to the wanted local line may be built and held awaiting the building up of the connection with the more expensive toll line, at which time the operator may cause the wanted local line to be signaled. It is the object of this invention to provide a system for accomplishing the desirable results above set forth. p

In accordance with this invention, a trunk circuit extending between an A and a B board may be connected at its incoming end with a telephone line, and a link circuit may be connected with the outgoing end thereof without applying ringing current to the telephone line until such time as the operator at the A board determines. There is associated with the trunk circuit apparatus, by means of which, when the operator at the central ofiiceX causes the momentary actuation of a switch, ringing current is connected with the wanted telephone line and is then automatically disconnected therefrom upon the response of the called subscriber.

For a complete understanding of this inventlon, reference should be had to the fol-. lowing description considered in connection with the accompanying drawing showing a telephone exchange system containing one embodiment of this invention. In the drawing, there is shown a telephone line A which a may. be connected in any desired manner with a cord circuit 0, located at a central oflice X, and another telephone line B terminating at a central office Y, at which is located the incoming end of a trunk circuit D, the outgoing end of which is located at the central oflice X. For convenience, the

operator at central oflice X will be hereinafter designated as the A operator, and the operator at central ofiice Y as the B operator.

Assuming that it is desired to build up a connection with and hold line B while the connection with'line A is being built up and to delay the application of ringing current to line B until the connection with line A has been built up, the Afoperator communicates with the B operator over an I order wire circuit (not shown) and receives a trunk assignment, after which the A operator inserts plug 5 of the cord circuit G into the jack 6 of the trunk circuit D and the B operator inserts plug 15 of trunk circuit D into jack 16 of-line B. The insertion of the plug 5 into the jack 6 causes I the lighting of supervisory lamp 36 and the operation of relay 7. Supervisory relay 8 does not operate when in-series with the high resistance left-hand winding of relay 7, but does operate when the low resistance righthand'winding thereof is included in the circuit in parallel with the left-hand winding, as will more fully hereinafter appear. If the B operator has not inserted the plug 15 into the jack 16 the operation of relay 7 causes the lighting of lamp 9 over a circuit from battery through the lamp 9 contact-of relay 7, lower normal contact of relay 10 and resistance 11 to ground, but if the plug 15 has been inserted into jack 16, the lamp 9 will'not be lighted by the operation of rerelay 10 and cut-ofi' relay 17. Relay 10, in

operating, closes its contacts 18 and 19 before contact 20 thereof is closed, so that fast operating relay 21 operates before the 'slow-to-operate relay 22 can attract. its armatures. The operating circuit for relay 21 may be traced from battery through the normal contact of relay 22, winding of relay 21, contact 18 of relay 10, contact of relay 7, winding of relaylO, sleeve contacts of the plug 15 and the jack 16 and the winding of cut-off relay 17 to ground,'relay 21,1in' operating, ,completesa locking circuit for itself, which includes its alternate contact. The winding of relay 21 is now connected in parallel with the lamp 9, forming a shunt. about and e'lfacin gthis'lampp Upon the closure of contact 20 of relay 10, following the'lclosure of contact '18, slow-operating relay 22 is actuated over a circuit from battery through the w nd ng of relay 22, contacts 20 and 18, contact of relay 7, winding of relay 10, sleeve contacts of the plug 15 andthe jack 16 and the winding of cut-off relay 17to ground. Relay 22, in operating, opens its normal contact in the initial energizing circuit of relay 21, and closes, at its right-hand alternate contact, a short circuit for and prevents the operation of the ringing relay 25. This short circuit also includes the alternate contact of relay 21.-

When the building up of the connection with line A is accomplished the A operator is suitably advised, and momentarily 'actuates a' key 27, causing the momentary openin of the circuit of relay '7, which re leases its armature and then attracts the armature againupon the closure of the circuit. The release of the armature of relay 7 opens the circuit of relay 21, which releases its armature, opening the short circuit of ringing relay 25. Relay 22 is made slow in releasing so that it'does not release its armatures while the contact of relay 7 is open for the short time. Upon the closure of the contact of relay 7 following the restoration of key 27 to normal position, ringing relay 25 immediately operates over a circuit from battery through the winding of ringing relay 25, right-hand alternate contact of relay 22, normal contact'of relay 21, contact of tripping relay 30, left-hand alternate-contact of relay 22, contact 18,

contact of relay 7, winding of relay 10, sleeve contacts of the plug 15 and the jack 16 and. the winding of cut-off relay 17 to ground. The operation of ringing relay 25 connects a source of ringing current 31, through the winding of tripping relay 30, to line B, thereby to cause the actuation of call bell 32 at the station of. line B. In respond- J ing to' the operation of the call bell, subscriber B removes the receiver from the switchhook, whereupon tripping relay "30 operates, opening its contact, thereby remov mg a short circu t from. the winding of reing.

1 ing supervis lay 21. Relay 21 thereupon operates and locks up, establishing a short circuit for ringing relay '25, which then releases its armatures to disconnect ringing current from the line and to complete the talking circuit. Immediately upon the completion of the talking circuit, supervisory relay 33 is operated, therebycompleting a circuit, through V the right-hand winding of relay 7, to connect it in parallel with the left-hand wind- The resistance in circuit with super- 1 visory relay 8 is thereby'decreased, permitting this relay to operate and establish a shunt circuit including resistance 28 for call ory lamp 36, whereby the lamp is effaced;

At the conclusion of the conversation, the

subscribers restore their respective receivers to the switchhooks. The restoration of'the receiver to the switchhook by subscriber B causes the deenergization of supervisory relay 33, which, in releasing its armature, opens the circuit of and removes the righthand winding of relay 7 from the circuit which includes the winding of supervisory relay 8, thereby causing the release of supervisory-relay 8. Upon the release of this supervisory relay, calling supervisory lamp 36 is lighted to furnish the A operator a disconnect signal. The A operator may now withdraw the plug 5 from the jack 6,

restoring the apparatus of the cord circuit- If desired, the momentary release of the trunk relay 7 may be accomplished by the VVIDOIIIQIIULI'Y withdrawal of the plug 5 from the jack 6. The key 27 may then be omitted.

v What is claimed is: V

1. A telephone exchange system comprise ing a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard connected with the trunk circuit, a source of ringing current, a telephone line, apparatus responsive to the connection of the trunk circuit with the telephone line for preventing the connection of the source of ringing current to the telephone line, a switch at the first switchboard,

means responsive to the actuation of the switch to connect the source of ringing'currentto the line, and a relay energized upon the closure of the telephone/line to disconnect the ringing current therefrom. I I

' 2. A telephone exchange circuit comprising' a trunk circuit extending from a first to a second cwitchboard, a link circuit at the first switchboard CQIlnected-with the trunk Cir ' phone line for preventing the connection of the source of ringing current to the telephone line, a switch at the first switchboard,

switching mechanism responsive to the actuation of the switch to connect the source of ringing current to the telephone line, and an electromagnetic switch responsive to the closure of the telephone line for causing the disconnection of the source of ringing current therefrom.

3. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit adapted to be connected with the trunk circuit, a source of ringing current, a telephone line terminating at the second switchboard, a ringing relay associated with the trunk circuit for connecting the source of ringing current to the line and maintaining such connection until the subscriber answers, an energizing circuit for the ringing relay, means operated upon the connection of the link circuit with the trunk circuit for pregventmg the establishment of said energlz ing circuit, and a switch at the first switchboard adapted when actuated to cause the release of said means thereby causing the energization of said ringing relay for connecting the source of ringing current with the line.

4. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard adapted to be connected with the trunk circuit, a telephone line terminating at the second switchboard, a signaling device, a relay in the trunk circuit energized upon the connection of the link circuit with the trunk circuit to cause the operation of the signaling device,

a source of ringing current, a ringing relay.

associated with the trunk circuit for connecting the source of ringing current to the line and maintaining such connection until the subscriber answers, means responsive to the energization of the trunk relay, a disabling circuit for the ringing relay established upon the operation of such means, and a switch at the first switchboard, said trunk relay being deenergized upon the momentary actuation of the switch to cause the release of said means thereby opening the disabling circuit of the ringing relay and causing the operation thereof to connect the source of ringing current to the telephone line.

5. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard connected with the trunk circuit, a telephone line terminating at the second switchboard, a source of ringing ourrent, a ringing relay for connecting the source of ringing current to the telephone line, a fast and a slow-operating relay energized upon the connection of the trunk circuit with the telephone line to prevent the operation of the ringing relay, a locking circuit for the fast-operating relay completed upon the energization thereof, a switch at the first switchboard, and a switching'device responsive to the actuation of the switch for opening the locking circuit and thereafter cooperating with the fast-operating relay to cause the operation of the ringing relay.

6. A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard, a trunk relay in the trunk circuit energized upon the connection of the link circuit therewith, a telephone line terminating at the second switchboard, a source of ringing current, a ringing relayadapted when energized to connect the source of ringing current to the telephone line, a fast and a slow-operating relay energized upon the connection of the trunk circuit with 'the telephone line to prevent the energization of the ringing relay, a locking circuit for the fast-operating relay completed'upon the energization thereof and including a contact of the trunk relay, a switch at the first switchboard controlling the trunk relay, and an energizing circuit for the ringing relay completed upon the denergization of the fast-operating relay followed by the energization of the trunk relay.

7 A telephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard, a trunk relay in the trunk circuit energized upon the connection of the link circuit therewith, a telephone line terminating at the second switchboard, a source of ringing current, a ringing relay adapted when energized to connect the source of ringing current to the telephone line, a fast and a slow-operating relay energized upon the connection of the trunk circuit with the telephone line to prevent the energization of the ringing relay, a locking circuit for the fast-operating relay completed upon the energization thereof and including a contact of the trunk relay, a switch at the first switchboard controlling the trunk relay, an energizing circuit for the ringing relay completed upon the deenergization of the fastoperating relay followed by the energization of the trunk relay, and a tripping relay responsive to the closure of the telephone line and cooperating with the fast-operating relay to cause the deenergization of the ringing relay.

8. A telephone exchan e system comprising a trunk circuit exten ing from a first to a second switchboard, a link circuit at the firstswitchboard connected with the trunk circuit,-a telephone line terminating at the 7 second switchboard, a source of ringing current, a ringing relay adapted when operated to connect the source of ringing current to,

the telephone line, a local relay responsive to the connection of the trunk circuit with the switchboard, and a switching device re-' 7 rent with the telephone line, a fast and a telephone line, a disabling circuit for the ringing relay established upon the energization of thelocal relay, a switch at the first sponsive to the actuation of the switch for rendering the disabling circuit inefi'ective thereby permitting the operation of the ringing relay.

9. Atelephone exchange system comprising a trunk circuit extending from a first to a second switchboard, a link circuit at the first switchboard connected with the trunk" circuit, a telephone line terminating at the second switchboard, a source of ringing current, a ringing relay adapted when energizedto connect the source of ringing curslow-operating'relay energized upon the v connection of the trunk circuit with the telephone line, a disabling circuit for the ringing relay established uponthe energization of the fast and slow-operating relays and including a contact of the fast-operating relay, a switch at the first switchboard,'and a switching device responsive to the actuation of the switch for rendering the. disabling circuit ineffective thereby permitting the energization of theringing relay to connect the source of r nging current to the line.

a second switchboard, a link circuit at the first switchboard adapted to be connected with the trunk circuit, a telephone line ter minating at the secondswitchboard,a switch at the first switchboard, a sourceof ringing current, a ringing relay associated with 10. A telephone exchange system compris- 111g a trunk circuit extending from a first to the trunk circuit for connecting the source I of ringing current to the line, and means responsive to the connection of the link circuit with thetrunk circuitto establish a d sabling circuit for the ringing relay, said

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