US2095712A - Telephone system - Google Patents

Description

Oct. 12, 1937. s, PETERSON 2,095,712

TELEPHONE SYSTEM Filed Feb. 5, 1936 BANKS CON N.

BAgIKS CONN.

TO LINE EQUIFMENT Ill-i INVENTOR. EDWARD S. PETERSON ATTORNEY.

Patented Oct. 12, 1937 UNITED STATES steam TELEPHONE SYSTEM Edward S. Peterson, Elmwood Park, Ill., assignor, by mesne assignments, to Associated Electric Laboratories, Inc., Chicago, 111., a corporation of Delaware Application February 3, 1936,Serial No. 62,084

13 Claims.

The present invention relates in general to telephone systems, but more in particular to an arrangement for giving a telephone subscriber a special type of service which will be referred to hereinafter as transfer service. A subscriber having this service is able to bring about a switching operation at the exchange, in effect for any desired period, which causes all calls intended for his telephone to be diverted to another telephone. The object of the invention is a new and improved arrangement of the foregoing character. I

The invention is especially useful for doctors, lawyers, and other professional people who are frequently absent from their offices and who do not wish to incur the expense of employing a secretary to answer telephone calls. It is also useful in the case of a doctor, for example, who has a secretary or attendant to answer calls during the day time, but desires to keep himself accessible to his patients at nights, when the office is unattended. In these and other cases the subscribers concerned, by contracting for the transfer service, are able to use their residence telephones for answering ofiice calls and thus secure the equivalent of 24-hour service in connection with their office telephone numbers.

The invention will be described more in detail with reference to the accompanying drawing, which is a diagrammatic circuit drawing showing the apparatus involved and the manner in which it is installed in a typical telephone system. Referring to the drawing, the reference letter A represents an automatic telephone station assumed to be at the office of a subscriber having the transfer service. B is the residence telephone, or any other telephone to which calls are to be transferred. The main distributing frame is indicated by reference letters MDF, and the intermediate distributing frame by the reference letters IDF. A transfer equipment, comprising four relays 3ll33, is indicated at TS.

The usual connections for a subscribers line are shown in the case of the line of substation B. The line 2 is cross-connected by means of a duplex jumper d at the MDF to a pair of protectors 5, indicated for convenience as fuses. From the protectors a cable pair leads to the line side of the IDF, where the line equipment is permanently connected. The foregoing are the connections required for outgoing service. The line is connected up for incoming service by running a jumper 6 from the terminal set on the line side of the IDF, to the set of terminals on the connector bank side which corresponds to the assigned telephonenumber. This jumper has three conductors (triplex) so as to connect through thethird wire, used for testing and busying purposes. The foregoing is common practice and is wellunderstood.

The transfer equipment, comprising a plurality of units such as TS, is preferably mounted as part of the automatic switchboard, on regular switch or repeater shelves, or on separate uprights. It is advisable to provide for jack mountingpusing the ordinary male and female jacks such as are used for automatic switches, although this is not essential. Assuming that jack mounting is used, each unit will require eleven jack connections, those for unit TS being indicated at 8 and 9. All the female jacks of jack connections such as 8' are permanently connected by cable to an extra group of protectors on the MDF, one pair of this group being indicated at I. .All the female jacks of jack connections such as 9 are permanently connected by cable to an extra group of terminals such as ill on the IDF. Thisextra group of terminals may be either on the line side, as shown, or on the connector bank side.

Station A is connected up for transfer service in the manner shown in the drawing. The old jumper on the MDF which connected line E to protector pair M has been removed and a new jumper 3 has'beenrun, connecting line I to the pair of protectors l which is associated with the transfer unit TS. At the IDF the old jumper, corresponding to 6, has been removed also, and three new jumpers l I, I2, and id, have been run fromthe particular nine terminals of group In which are associated with transfer unit TS. Jumper I l serves to connect the terminals M43 with the terminals on the connector bank side of the IDF whichare associated withv the office telephone number. Jumper l2 connects the terminals 4446 with the residence line, that is, the line of telephone station B. This jumper may pickup the line of station B at the connector bank side of the IDF as shown, or at the line side. Jumper l3 connects the terminals 4'l49 with the line equipment associated with station A.

It will be assumed now that the key at station A is normal, as will be the case if the subscriber or attendant is present. If the receiver is removed to makean outgoing call the transmitter and receiver are bridged across line I, closing a circuit for relays 3i and 33 in series. Both these relays operate. At 39 relay 3| connects terminal 49 with terminal 43 via 53, thus connecting through the third wire 56 associated with the line equipment to the third wire 51 extending to the connector bank contactsets of station A. At 38 relay 3! attempts to close a circuit for relay 32, but fails to do so because relay 33 opens the circuit of relay 32 atAIl. At 50 relay 33 places a bridge across the'line conductors 54 and 55, extending via 4'! and 48 to the line equipment of station A, thus placing the line in calling condition.

The system may use either line switches or finders to extend calling lines to idle trunk lines. In any case as soon as an idle trunk is connected with ground is extended back over the third wire 56, making the line busy to the connectors, and operating relay 30. Relay shunts contacts 33 at 31, and at and 33 disconnects line I from V relays 3! and 33 and extends it through to line,

third wire 51, and relay 30 and'the' cut-off relay fall back. 7

' by ,disconnectingthe three terminals 4|, 42, and

conductors 54 and 55.. Relays 3| and 33 now fall back, but without effect. The automatic equipon the third wire 56 to 'hold relay 30in operated I position. The callis completed bydialling in the usual manner. The connection is released by hanging up the receiver at station A, which permits the automatic switches to restore. This removes ground from the third wire 56 and allows relay 33 to fall back.

When station A is called, the connector in use places ground on the third wire 51,, thereby closing a circuit over the third strand of jumper II, 43, 53, and winding of relay 30 to battery. Relay 3!! accordingly energizes and connects conductors E i and 55 through to the called line, disconnecting relays 3| and 33 at the same time. Relay 30 also connects the third wire 51 through to third wire 55 at 31, and ground is thus extended to the line equipment of station A, where the cut-off relay is operated in the usual manner. Ringing current is now transmitted over line I from the connector to operate the bell at telephone A, and the. call is answered in the usual manner. the connector is released, ground is removed from It will now be assumed that the telephone station A is left unattended for a while. Before leaving the premises the subscriber or attendant will operate the key K, which may be in thebase of the telephone or at any convenient place. The key is of the type which stays in operated position. If desired the receiver may be removed and it off after the key has been operated, as an aid to the subscriber in reminding him torestore the key when he returns.

When key K is operated it grounds the nega- I tive side of line I and operates relay 3|. Relay 33 remains deenergized, whether the receiver is removed or not. a circuit at 38 for relay 32. The latter relay, on energizing, operates contacts 5I,'52,,and 53, thered3 from their normal associationwith line I and connecting them instead with terminals 44, i5, and 46, which are associated with line 2 overthe triplex juniper I2. Relays 3| and 32 remain energized while key K remains actuated, or while the telephone station A is left unattended.

If telephone A is called during this period, the. connector in use places a ground on third wire 5'E, which is now connected with third wires 58 and 59. at 53. The grounding of third wire 58 operates the cut-01f relay of the line equipment When On energizing, relay .3 I closes,

associated with line 2, the line of telephone station B, and the grounding of 59 guards the line against intrusion by another call. Ringing current is now transmitted from the connector via the bank contacts of station A, the jumper II, contacts 5I and 52 of relay 32, and jumpers I2, 5, and 4 to line 2, operating the bell at telephone B. The call is answered at that telephone in the appropriate manner, and so far as the calling party is concerned the service is the same as if the call had been answered at telephone 2.

It will be evident that while the transfer relay 32 is in operated position an office call will make the residence line busy, while a call to the residence line will make the office line busy. This limitation is inherent from the nature of the system and is not a particular drawback from the standpoint of selling the service. As regards the 1 possible loss of a residence call due to a call on the office line, the subscriber is willing to subordinate his residence service to the maintaining of continuous service on the office line; and as regards the possible blocking of an ofiice call by reason of the residence line being in use the subscriber can give instructions su tably restricting the use of the residence phone while the transfer unit is in transferring condition.

It will be assumed now that the subscriber returns to his office. The receiver is replaced at telephone A, if it was left off, and key K is restored. Relay 3I accordingly falls back and breaks the initial energizing circuit of relay 32, which falls back also unless the residence telephone B is engaged in a call. In the latter event relay 32 is locked up to the third wire through contacts 60, and remains energized until the call is over with. This provision is made because the call in which telephone B is engaged may be a call intended for telephone A, being answered at telephone B, and if relay 32 were permitted to fall back while conversation was going on the call would be interrupted.

If the receiver is removed at telephone A to make an outgoing call while relay 32 is locked up, relays 3! and 33 energize and the latter relay initiates the call by placing a bridge across conductors 54 and 55 at 50 as previously described. This operates the calling equipment, line switch or finder, and ground is applied to third wire 58, operating relay 3!] by way of 39. Relay 33 looks itself to the third wire at 3'! and disconnects relays SI and 33. During the short interval in which relay 33 is operated it makes a test to ascertain if relay 32 is locked up due to a call intended for telephone A, or due toa regular outgoing or incoming call involving telephone B.

Explaining this operation, when relay 33 energlzes it opens the multiple connection between the third wires of lines I and 2 at the springs controlled by armature 6|, and at the same time by means of armature GI and its working contact it grounds the third wire 58 of line 2. There are two cases to be considered now. In the first case relay 32 is locked to ground on the third wire 58 or 59 of line 2, and accordingly when the multiple connection to the third wire 51 is broken relay 32 at once falls back and breaks its own locking circuit at 60. The ground applied to the third wire of line 2 by the operation of relay 33 does no harm, and it is taken off at 52 as soon as relay 32 falls back. In the second case relay 32 is locked to ground on the third wire 5'! and of course stays locked. The ground applied to third wire 58 by way of 52 and 5! holds the cutoff. relay of line 2 energized, and this same ground connection on 59 maintains line 2 'in busy condition to prevent intrusion by another call. When relay 33 falls back due to the operation of relay 3!] the thirdwires 58 and 59 are again joined to third wire 51 and the temporary ground connection through 5! and 62 removed. The circuit remains in this condition, with relay 32 locked up, until the connector maintaining ground on 5'! is released- The arrangement just described is not essential but it is a desirable feature, as it provides for automatically unlocking relay 32 responsive to an outgoing call from station A if the relay is locked up due to a regular call on line 2, a

call in which the transfer service is not involved.

The subscriber at station A can make use of this feature if he desires by always momentarily removing his receiver after restoring the key K, which will insure the immediate reestablishment of incoming service to station A, unless a transferred call is actually in progress.

If the feature of selectively unlocking relay 32 is to be left out, the springs 6i and 62 are omitted and the front contact of spring 53 is Wired direct through a jack connection 9 to terminal iii. Or in a unit like the one shown in the drawingthe armature spring 6! can be easily adjusted so that it will not engage its working contact. Relay 32 will then remain; locked up after the key K is restored provided there is a call on line 2, and it cannot be unlocked until the call is released.

Another modification involves the omission of the locking contacts 6!), and may be used if the subscriber desires 'to definitely insure the immediate restoration of incoming service at telephone A upon restoration of key K, even though it may result in the interruption of an office call being answered at telephone B. Ifthis modification is used, however, the subscriber should be ininstructed to promptly remove his receiver and challenge on the line after the key K is restored, so that if a transferred call was in progress he can take it over. Explaining this a little further, it will be seen that when relay 32 falls back on restoration of the key, the third Wire 51, which is grounded if a transferred call is in progress at the time, will be switched back at 53 to its normal connection with relay 30, operating this relay. Relay 3E] closes the talking circuit at 35 and 36 and when the subscriber at station A comes on the line he can pick up the call.

The transfer equipment is adapted for use in connection with other types of telephone systems than the one specifically referred to herein. One system in extensive use is similar to the one described, except that the connector bank cables and the line equipment cables have their positions interchanged at the IDF. Obviously the transfer units can be used in this type of system by merely reversing the jumpers such as H and I3 at one end or the other. Other systems are known in which no IDF is used and the calling and called branches of the lines are permanently connected. These permanent connections, of course, have to be opened up, by unsoldering at the cable terminals, in order to insert the transfer units. In any case the units will work in manual systems as well as in automatic systems. In manual systems, however, the arrangement is generally such that the third wire of an engaged line is connected to battery instead of ground to make the line busy and to operate the cut-off relay. In order to accommodate the transfer units to this arrangement the relays such as 30 are connected to ground instead of to battery.

The invention having been described, that which is believed to be new and for which the protection of Letters Patent is desired will be pointed out in the appended claims.

What is claimed is:

1. In a telephone system, an ofiice line, a residence line, a device at the station on the oifice line adapted for sustained operation to modify the line circuit'to indicate an unattended condition so long as said device remains operated, and means at the exchange sensitive to the modified line circuit and effective invresponse thereto to divert calls intended for the ofiice line to the residence line.

2. In a telephone system, a subscribers line extending to the exchange, a branch over which the line is called, a transfer relay for switching said branch into multiple connection with the corresponding branch of another line, and controlling means for said relay effective to operate it if one side of the line is grounded at the subscribers station and not operate it when the receiver is removed.

3. In a telephone system, a subscribers line extending to the exchange, calling and called branches normally disconnected from the line, a transfer relay for switching the called branch into association with another line, means for opcrating said relay responsive to grounding the line at the subscribers station, means responsive to the removal of the receiver when the line is ungrounded for initiating a call over the calling branch, and means responsivev to the initiation of the call for extending the line through to the calling branch.

4. In a telephone system, a subscribers line extending to the exchange, a branch of the line over which the line is called, a transfer relay for switching said branch into multiple connection with the corresponding branch of another line, means for energizing said relay from the subscribers station, and means for holding said relay independent of said energizing means providing the latter is released by the subscriber at a time when the said first branch is in use.

5. In a telephone system, a subscribers line extending to the exchange, a branch over which the line is called, a transfer relay for switching said branch into multiple connection with the corresponding branch of another line, means at the subscribers station for energizing said relay, means for holding said relay after the said energizing means is released provided either of said branches is in use, and means responsive to the removal of the receiver at the subscribers station for testing to ascertain which branch is in use and for rendering said holding means ineffective if the branch in use is the branch associated with the other line.

6. In a telephone system, a plurality of transfer units, each unit including a relay for directly switching the conductors over which access is had to a line when called into multiple connection with the corresponding conductors of another line, permanent cable connections between said units and the main and intermediate distributing frames, whereby any subscribers line may be equipped with one of said units by running jumpers at said frames, and means at the station on each line so equipped for maintaining the relay in the associated unit energized while the subscriber is absent from the station.

'7. In a telephone system, a subscribers line,

, normallyvdis'connected calling branch extending necting the subscribers line to the line conductors of the calling and called branches, and for connecting said test conductors together.

8. In' a telephone system, a subscribers line, a branch of said line accessible. to connector switches, a second branch extending to line equipment, test conductors included in said branches normally disconnected from each other, a relay energized over the test conductor of the connector branch when the line is called, and contacts on said relay for connecting said test conductors together.- r

9. In a telephone system, a subscribers line, a

to line equipment for initiating outgoing calls, two relays normally bridged across said line and responsive to the removal of the receiver, contacts on one line relay for initiating, the operation of said line equipment, a third relay connected'to the test conductor of said calling branch by the other of said line relays, said third relay being energized over said test conductor responsive to the operation of said line equipment, and contacts on said third relay forlocking I itself to said test conductor, for disconnecting said line relays, and for connecting the subscribers line with said calling branch.

.10. In a telephone system, a subscribers line, a called'branch for said line normally disconnected from said line, a relay energized when the a line is called to connect said called branch to the line; a-transfer relay controlled over said line from the subscribers station, and contacts on said transfer relay effective when the relay is in energized condition for maintaining said called branch connected in multiple to another subscribers line and for preventing the energization of said first relay when the said first line is called.

11. In a telephone system, a subscribers line, a transfer relay for diverting calls intended for said line to another line, two line relays normally bridged across said line, one relay being responsive to grounding thev line at the station and both relays being responsive to bridging the line at the station, and a circuit for said transfer relay controlled jointl by said relays. 7 u

12. In a telephone system, a subscribers line,

a a key at the station on said line, a relay at the exchange held energized over one side of the line while said key is in operated position, a transfer relay for diverting calls intended for said line to another line, a circuit for said transfer relay closed by said first relay, another relay energized over said first line responsive to the removal of the receiver, and contacts on said last mentioned relay for disabling said circuit to deenergize said transfer relay.

13. In a telephone system, a main frame on which subscribers lines are terminated, an intermediate frame on which calling and called line branches are terminated, a transfer unit comprising a transfer relay and a plurality of controlling relays, connections from said unit to a set of terminals on said main frame and to three sets of terminals on said intermediate frame, a jumper connecting said first set of terminals to a subscribers line, and three jumpers connecting said three sets of terminals, respectively, with the called branch of said subscribers line, the calling branch of said subscribers line, and another subscribers line, the said unit andconnections including said jumpers constituting means whereby 'the station on said first line can extend and receive calls and whereby incoming calls can be diverted to said other line at times when the station is unattended.

EDWARD S. PETERSON.

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