US2346113A - Auxiliary telephone apparatus - Google Patents

Description

A ril 4, 1944. c. s. RHOADS AUXILIARY TELEPHONE APPARATUS Filed April 22, 1943 B'Y C. YW

INVENTOR ATTORNE Patented Apr. 4, 1944 AUXILIARY"TELEPHONE APPARATUS 'Oharles stanley Rhoads, Albany, N. Y., assignor :to American'Telephone andTelegraph m- 1: pany;-a corporation of New York 'I.ApplicationApril 22, 1943, Serial No. 483,983

3 Claims.

This invention relates generally to telephone systems. More particularly,'.thisinvention relates to apparatus for signaling between two telephone ofiices over trunk or other lines. Still more particularly, this invention relates to auxiliary or emergency equipment for use at telephone offices to provide iacilities for signaling between the offices under abnormal conditions.

It sometimes happens that a community or hamlet too small to justify an ordinary manual exchange is located near a city provided with a regular telephone exchange or exchanges. Such an outlying hamlet may be provided with te1ephone service by means of a community dial ofiice which may be equipped with relatively simple automatic switching machinery to enable the local subscribers to dial each other. -An operator in the city may establish -a direct connection over one of a group of trunks extending to the community dial ofiice to any desired subscriber coming into the community dial oiiice, and any local subscriber who desires a connection to the city may by dialing be connected over one of these trunks to any of the city subscribers. Such community dial offices are usually unattended, except at such time as maintenance or inspection employees make temporary Visits to inspect or test the apparatus at the office.

It may happen that when an employee has been dispatched to the community dial ofilce to test or inspect the equipment he may find that the equipment has been partially or totally destroyed, or that the power supply has been rendered inefiective. In that case he will be unable to communicate with the operator at the manual or operator ofiice. As the community office may be several miles distant from the main office, it

will be necessary for the telephone employee to return to the operator ofiice to deliver hismBssage. This is, of course, time consuming and expensive.

Accordingly it is proposed to equip telephone oifices such as community. dial offices and manual or operator. ofices and the-like, with auxiliary or emergency equipment to enable signals to be transmitted between these ofiices'whenever the regular equipment has been disabled. The

apparatus of this invention involves'the employment of equipment at the 'various 'oi'hces which will not consume'current under normal conditions; although at the same time the equipment'will always'bebonn'e'cted to the telephone not affect normal telephone transmission over the line or trunk.

In general, the apparatus of this inventionwill comprise a gas tube at each oflice which is connected to but one of the conductors of the telephone line or trunk so that it may be fired only at times when a ringing generator is connected to that particular conductor of the line or trunk. When the gas tube at the'station is fired in response to the application of the ringing generator voltage to the particular conductor, it will be employed to provide a signal to attract theoperators attention at the time. The ringinggenerator voltage for firing the gas tube may be supplied by a magneto generator set of well known type. The magneto generator set can produce an alternating voltage of sufficient magnitude to cause the gas in the tube to become ionized. The apparatus at each oflice may also include, in addition to a visual or, audible indicating device, th usual form of telephone transmitter and receiver to permit the parties to speak to each other. Whatever sources'of' D. C. potential may be required may be supplied 'by dry cells. In accordance with this invention 1 all of the auxiliary emergency equipment at the stations will be efiectively dissociated from the telephone line or trunk and will not interfere with normal signaling and communication over the telephone line or trunk. Moreover, the auxiliary or emergency equipment, although connected to p the telephone line or trunk, may be'located at a connect a subscriber in the community dial area to a subscriber in the area'of the operator ofiice. The regular office equipment so far as it may relate'to this invention is shown above the-dotted line. Below the dotted line will be-found the auxiliary or emergencyequipmentwhichis additional equipment different from that heretofore used in such offices and may be employed only 3 in emergencies.

" line or'"trunk" foruse lrr'emergencies; and will now be only briefly described.

The regular equipment ofthe two officeswill The windings of relays W and P at the community dial ofiice and at the operator oflice, respectively, are connected in a series circuit which includes the upper winding of relay W, the upper secondary winding of the repeating coil RLI, the upper armature and normal contact of relay U, the upper conductor of trunk TK, the upper primary winding of repeating coil RLz, the windings of relay P, the lower primary winding of repeating coil RLz, the lower conductor of trunk TK, the lower armature and normal contact of relay U, the lower secondary winding of the repeating coil RLi, the lower winding of relay W, battery to ground. The current that traverses the windings of the relays W and P will be insufiicient to operate these relays, but they may be operated as will be described hereinafter whenever a call is made from, for example, the subscriber connected to the community dial omce to a subscriber connected to the operator oflice,

When a call is being made by a subscriber of the community dial ofiice to a subscriber connected to the distant operator office, then in response to a predetermined dialed number, battery will be connected to the conductors T and R,

causing relay S to operate. Positive battery will be connected to the tip conductor T to energize the upper winding of relay S while ground will be connected to the ring conductor R to energize the lower winding of relay S. The operation of relay S will cause relay U to operate over an obvious circuit established by the armature and make contact of relay S. When relay U operates, it will reverse the direction of current fiow from the battery connected to the lower winding of relay W through the windings of relay P. This reversal is established by the upper armature of relay U which connects the grounded upper winding of relay W to the lower conductor of trunk TK and by the lower armature of relay U which connects at the lower winding of relay W to the upper conductor of trunk TK. Upon the reversal of current through the windings of relay P, relay P will be operated. The operation of relay P will cause the lamp LP1 to light, thereby attracting the atention of the operator at the operator oflice.

In response to the visual signal provided by lamp LPI the operator at the operator office may answer the call by inserting her plug into the jack JK], in the usual way. This will connect battery to the tip and ring terminals of the jack JKI to establish a flow of current through the secondary windings of the repeating coil RLz and the winding of relay V, and hence relay V will be operated. The closure of the contact of relay V will provide a shunt path across the left-hand portion of the winding of relay P, thereby materially reducing the resistance in the circuit of the remaining winding of relay P. This substantial reduction in resistance will allow a greater current to flow through the windings of relay W over the circuit previously traced, and hence relay W will be operated. The relay W may be used to control coin collector apparatus and for other purposes.

Suppose that in an emergency a repairman or other authorized person has been dispatched to the community dial oifice, and upon arriving at the office, finds some of the regular equipment out of order or the battery supply disabled so that he is unable to use the regular equipment to communicate with the operator oilice operator. He will find at that ofiice auxiliary equipment which will enable him to signal and converse with the operator at the operator ofi'ice.

To signal the operator omce the party at the community dial office will operate the magneto generator G of the magneto set located at that office while the receiver RR. is held on its switchhook. This will cause an alternating voltage to be generated and transmitted over a circuit which includes the condenser K1, the magneto generator G, the lower conductor of trunk TK, the control gap of the gas tube TB1 at the operator ofiice and ground. The anode AN1 of the tube T31 is shown connected to the left-hand winding of relay A, and hence this winding of relay A will receive current supplied by the magneto generator G after the tube TB1 becomes ionized. It will be noted also that the gas tube TB2 at the community dial oflice is connected to the generator G, and hence this tube will likewise be fired. Inasmuch as the anode AN2 of tube TBz is connected to ground through a ringer or bell BL, the ringer or bell will be operated in response to the generated alternating voltage.

As relay A becomes operated in response to the alternating voltage emanating from generator G, it will be locked in its operated position over a locking circuit which includes the armature and make contact of relay A, its right-hand winding, the contact 0 of the jack JK3, the lamp LP2, battery and ground. As the lamp LP; is included in the locking circuit, the lamp LPz will be illuminated and maintained in that condition to continuously indicate to the operator at the operator oifice that an emergency call is being made to that ofiice. The relay A will remain locked and the lamp LP2 will remain illuminated until the operator at that oifice answers the call.

The emergency call may be answered by the operator by inserting the plug of her talking set into the jack JK3. The lamp LP2 will then be extinguished by the opening of contact C. This will connect her talking set through condenser K2 across the trunk TK. Upon the removal of the receiver RR from the hook at the community dial office, the receiver RR. will be connected across the trunk TK by two conductors, one of which includes the secondary winding SW of the magneto coil, the other conductor including the condenser K3. A the transmitter TR. of the telephone set is connected to the circuit of the primary winding PW of the induction coil of the magneto set, it will also be rendered efiective so that the party at the community office may talk with the operator ofi'lce operator.

Should the party at the community dial office hang up before the operator has completed her conversation with him, or if the operator should desire to recall that party, the operator will connect the plug of her ringing generator set with the jack JKz. This will cause the gas tube TBz of the community dial oifice to receive ringing current over a circuit which includes the tip and ring contacts of jack JKz, the lower conductor of trunk TK and the control gap of tube T32 and ground. In response to this ringing current the gas tube TB: will become ionized and the bell BL will be sounded. In answer to this signal the party at the community dial oifice may then remove his receiver RR from the switch-hook and receive the message from the operator at the distant ofiice.

It will be observed that the additional auxiliary equipment at the two oifices is simple and inexpensive and that, although permanently connected to the trunk TK,.itwill have practically no effect upon the transmission characteristic of the trunk TK. Hence the auxiliary equipment will not interfere in any Way with the normal transmission of signals over the trunk TK. Moreover, normal transmission over trunk TK will not operate any of the auxiliary equipment. Whatever batteries are used in the auxiliary equipment may be dry cells, and they will have a long life due to the small drain of current required to provide this occasional service. The tubes T281 and T32 may be any type of gas tubes well known in the art, although tubes of the 333A type have been used successfully for this purpose.

While the emergency equipment has been shown connected to a community dial office and to an operator or manual ofiice which is attended by an operator, it will be understood that this emergency equipment may be provided for any telephone ofiices whatever. Moreover, the emergency or auxiliary equipment may be located at places difierent from and outside of the central ofiices, if so desired. It will also be understood that the arrangement shown'and described in the drawing may also be used as regular telephone equipment, if so desired.

While this invention has been shown and described in certain particular embodiments merely for the purpose of illustration, it will be understood that the general principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. In a telephone system, the combination of two telephone oflices having telephone and signaling apparatus and interconnected by a telephone line so that signals may be transmitted normally over said line, apparatus for providing emergency service over said telephone line, said apparatus including a gas tube at each telephone ofiice connected to but one of the conductors of the telephone line, means for applying ringing current to the same conductor of the telephone line for firing said gas tube, a ringing device at each ofl'lce which responds to the firing of the associated gas tube, and means including a telephone set for connection across the telephone line to permit talking currents to be transmitted over the line.

2. The combination of two telephone offices, a two-wire line interconnecting said telephone offices, said telephone ofiices including apparatus for normally signaling over said line, auxiliary apparatus for signaling over said line without disturbing normal signaling between said telephone offices, said auxiliary apparatus including two gas tubes, one located at each ofiice and connected to but one of the wires of said line, an indicating device at each ofiice controlled by the gas tube at that office, a magneto generator at each office which may be connected to one wire of the line for ionizing the gas of the tubes at said ofiices, and means for transmitting and receiving telephone currents over said line.

3. In a telephone system, the combination of a main ofiice which is attended by an operator, a community dial oflice which is usually unattended, a trunk interconnecting said ofiices, said ofiices including apparatus suitable for normally signaling each other over said trunk, emergency signaling equipment at each ofiice, the emergency signaling equipment at the community dial ofiice including a first gas tube connected to but one of the conductors of said trunk and a magneto set which may be operated after the first gas tube has been fired, the emergency signaling equipment at the main oflice including a second gas tube connected to the same conductor of said trunk, a relay controlled by said gas tube, and an indicating device controlled by said relay, said emergency signaling equipment at both offices being continuously connected to said same conductor of the trunk and having substantially no effect upon normal transmission between said offices over said trunk.

CHARLES STANLEY RH-OADS.

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