US2186246A

US2186246A - Communication system

Info

Publication number: US2186246A
Application number: US104755A
Authority: US
Inventors: Kiner Glenn
Original assignee: Kellogg Switchboard and Supply Co
Current assignee: Kellogg Switchboard and Supply Co
Priority date: 1936-10-09
Filing date: 1936-10-09
Publication date: 1940-01-09
Anticipated expiration: 1957-01-09

Description

Jan. 9, 1940 G. KINER COMMUNICATION SYSTEM,

4 Sheets-Sheet 1 Filed Oct. 9, 1936 nuetzlur' E [El-1n KznEr' Jan. 9, 1940. E

COMMUNICATION SYSTEM mm\ v .7

l must-717T:

H nr'ne 4 Sheets-Sheet 2 EIEnn Kin/Er y Filed Oct. 9, 1936 Jan. 9, 1940.

G. KINER COMMUNICATION SYSTEM File d Oct. 9" 1936 4 Sheets-Sheet I5 TFHIE HEP ElEr-u'z KJFIEI" Jan. 9, 1940- G, KlNER coMMimIcA'rIou SYSTEM Filed Oct. 9, 1936 4 Sheets-Sheet 4 I schematic Patented Jan. 9, 1946 fi ment ooMMUNioAriou sYs'rnM Glenn Kiner, Earl: Ridge, lElL, assignor to Kellogg Switchboard and Supply; v(3cinpany, Ehicago, lllL, a corporation of Illinois Application .Qctober 9, lQSS Q'Serial No. 104,755.

16 Claims;

My invention relates to a selector system for telegraphlines, and more particularly to that type of line used for printing vtelegraphs. In systems of this type it has been usual to have a plurality of printers associated with one line and means have been provided for connecting certain desired stations thereto, but my system provides means located at a central point for automatically connecting anyone station t'o any other station. s

A feature of my invention is the provision at a central point of selecting means controlled from a distant station to connect the said distant station to any other station terminatingat the said central station to the exclusion of the other stations.

vision in the selecting means of a selector switch an electromagnetic means controlling said selector'switch, whereby the selector switch can be stepped, or may be driven to a group contact and thenstepp ed to a desired contact in the group, or may he driven-to a group contactand then 7 permitted to select any idle line in that group. Other features will become apparent upon fur-v ther perusal of the specification, and together with the features pointed out, willloe explained hereinafter, reference being made to the accompanying drawings comprising. Figs. 1 to 4 inclusive, which drawings, when placed'from left to right in their numerical order,. show a full system. The present invention will be best understood from a consideration of the following detailed description taken in connection with the" ac coinpanying drawings; with the understanding,

however, that the. invention is not confined to any. strict conformitywith the showing of the drawings, but maybe changedor modified so long as such changes orinodifications no material departure from the salientfeatures of the invention as. expressed in the appended claims. 1

general description of the system.v The invention provides means whereby a group of tele ,telegraph line terminates in a selector of the type shown. Each selector comprises a group of impulse relays which control the movement of a Another feature of my invention is the pro-' circuit arrangement of my selector,

It is believed an understanding of the present. disclosure will be facilitated by a preliminary rotary switch, whereby the said switch isdriven' to a certain group contact. In the contact bank (33d associated with the switch every tenth'or tens. group contact is adapted to be connected to ground potential by a corresponding counting 5 relay 132,02, D32 or E2 oiFig. 2, these relays being operated. successively when the first digit of the wanted number is dialed. Thenfother switching relays operate to place the selector switch under the direct control of the dialing means at the station to step the said selector switch to any desired contact in the group.

relay means are provided to drive the selector switch to a certaingroup and then permit this switch to hunt ioi an idle line in the group. The general operation of my system is as follows: The operator at a station, as shown in Fig. 1,

- desiring to connect'her station to another station associated with/the central station, will operate 20 the dial key DK and then proceed to dial the number of theydesireol station The first actuation ofthe dial D causes the off-normal spring ON associated therewith to assume an alternate position to close an energizing circuit for the offrnorma l relay OFR which opens the shunt circuit around the polarized line relay PLR to fperrnitthe saidrelay'to operate to condition the telegraph line "for dialing. 'As the dial D' re-" turns to -its normal position it interrupts the 5 current flowover the telegraph line to-dial the first'digit in the well knownmanner. The irn pulse relaysshown in Fig. 2. are affected by the interruption of the current flow over the line and operate to ground the tens contact in the contact bank associated with'the selector switch, and at the same time closela self-interruptin -operating' circuit for the motor magnet, which causesthe selector switch to be driven to ground! a't'the tens contact as'the impulserelays are rapidly venergized and deenergized in succession, responsiveto the dial impulses. The-selec tor switch brushes will move continuously step by step to the selected tens contact.

I Due to the usual change-over operation follow l5 g cause the selector switch, when it stops upon a predetermined contact of such a group of lines, to hunt for an idle line in the group. In such a connection the operator will dial the number in the usual manner and the dialing of the first digit will ground the proper tenscontact and the dialing of the second digit will step the switch wipers to the group contact at which time the change-over means operate and cause the switch to step until it locates a set of contacts leading to an idle line.

Having described in general the circuit of the apparatus-used in my invention, I will next describe the detailed operation of the same in establishing the different connections. Assuming that the subscriber at station A Fig. 1 desires to be connected with another subscriber, he will operate his dial key D1; which closes alternate contacts ii and ii. to place the dialD in a series connection with the line L which extends to the central ofiice. The flow of current from the central oflice is normally present on this line and may be traced from battery at relay 2d of through normal contacts l3 and it, line L,, normal contact l5 of relay SLR-in Fig. 1, through the winding of dial relay DR, and over the line L, through the-dial key DK, the winding of the polarized start relay PSR, normal contact it of off-normal relay CPR, and through the telegraph printer TP to' ground.

Assuming that the number of the desired station is 55, the operator will dial the first digit, or 5, by operating the dial D in the usual manner. An energizing circuit for the relay OFR is closed at cit-normal contacts ON of the dial D. The

relay OFR closes a locking circuit for itself through its alternate contact ll to ground at alternate contact is ,of release key RE. The

relay OFR opens contact it which removes the shunt around the polarized line relay PLR, which will thereupon be energized by current flowing over the line in the previously described manner. The closing of alternate contact IQ of relay PLR establishes an obvious energizing circuit for the dial battery relay DBR which energizes to close alternate contact illlto connect the dialing battery DB to the line L which reverses the flow of current in the previously described line circuit and causes the operation of the polarized start relay PSR which closes its alternate contact M to close a start circuit for the usual motor which is used for driving the telegraph printer.

The first interruption of the flow or" current over the line by the dial D causes the dialing relay DR to deenergize and restore its contact 22 to its normal position, which places ground upon the dialing conductor DC to close an energizing circuit for the switching relay SW the first inipulse relay Al. The relay SW is operated by current flowing from grounded battery'through the winding of'relay SW, normal contact 23 of relay SWA, dialing conductor DC, alternate contact 2d of relay Dl-IR, which is of the slow-to-- release type and holds up even though its energizing circuit has been opened at contact 22 of relay DR, to ground at normal contact 22 of relay DR. The first impulse relay Al is operated by current flowing from battery through the closed contact 25 of relay SWD in Fig. 4, conduct-or 25, closed contact Zic oiimpulse relay El, and through the contacts li'ld, Tic, Zl'b, the Winding of relay Al, normal contact 28a, conduct'or 29, normal contact 23' of SWA, and the dialing conductor DC to ground at normal contact 22 of dialing relay DR. When the line L is restored to normal.

tactv 28a to extend the dialing conductor DC to the next set of impulse relays. Meanwhile an obvious energizing circuit for impulse hold-over relay IHR has been closed at alternate contact 36a of relay Al and said relay IHR is locked up by current flowing from grounded battery through winding of relay II-IR, its alternate contact iii, conductor 32, closed contact 33 of relay l8, conductor 3%, normal contact 35 of relay ll, conductor 38 to ground at alternate contact 3'! of relay DI-IR in Fig. l.

The restoration to normal of contact 22 of dial relay DR, due to the second interruption by the dial D, causes the energization of the second impulse relay Bl, by current flowing from grounded battery through alternate contact 38a of relay AZ, through Winding of second impulse relay Bl, normal contact 23b, over the dialing conductor DC to ground at normal contact 22 of relay DR; The relay Bl closes its alternate contact Bill) and immediately upon the opening of contact 22 by the reenergization of the dialing relay DR, after the second impulse, the relay B2 is operated by current flowing from battery through contact 25 of relay SWD in Fig. 4, over the previously traced circuit, and through contact 2'51), alternate contact 3% of relay Bl, the Winding of relays Bi and B2 ground at alternate contact 3% of Bi. The operating circuit for the impulse relays Al and A2 was opened at contact 3% of relay BI and they accordingly The operation of relay B2 disconnects, by the opening of contact 28?), the second impulse relays Bi and B2 from the dialing conductor DC and closes contact lilb to place ground potential upon the first tens contact in the contact bank CB l.v This potential can be traced from ground, through the winding of relay SCR, conductor 53', normal contacts Elle, 40d, lilo, or the comiting chain or impulse relays, alternate contact 48b of relay B2 and conductor 99 which leads to the first-tens contact.

Relay B2 energizes and closes alternate contact Mb to establish an energizing circuit for the motor magnet MM, which is. energized by current flowing from grounded battery at relay SWD in Fig. at, through the resistance RA, conductor il, normal contact d2, through the winding of the motor magnet MM, normal contact 33 of relay MSW, normal contact 34 of the motor magnet MM, conductor 45, normal contact l'd of hunt control switch relay I-ICA, conductor 41, alternate contact Mb of relay B2, conductor 48, normal contact 39 of relay RCR to ground. The motor magnet MM opens its contact Ml to interrupt the energizing circuit and the motor magnet MM is deenergized and steps the wipers WI W2, W3 and W3 one step. The motor magnet MM is so constructed that it moves the wipers W! to W4 one step each time it is deenergized.

Upon its deenergization the energizing circuit is again step the wipers. This action is continuous until the wiper W4 engages one ot the tens contacts which is grounded.

In. the meantime, however, the third interruption of the line has been caused by the dial D and the dial relay, DR has been deenergized to again ground the dialing connector DC to establish an energizing circuit for the third impulse relay Cl, which relay is energized by current flowing from battery, through alternate contact 38b of the second impulse relay B2 through tact in contact bank CB4 but the closing of contact 450 of relay G2 has placed ground potentialv on the next tens contact. The opening of contact 3822 of relay B2 removes battery from the energizing circuit of relay Cl, but a substitute.

battery has been connected thereto at contacts 390 and 21c of relay CL and, as soon, as the line L has again been closed and the relay DR' again. energized to remove ground from the dial ing conductor DC, the relay C2 is'energized by current flowing from battery at armature 25 of relay SWD over the previously traced circuit, through the contacts 210 and 390, the windings of the relays C1 and C2 to ground at 350. The closing of alternate contact tic of relay C2 con tinues the self-interrupting energizing circuit" of the motor magnet MM. This circuit is closed at contact Me before it is opened at contact ilb of relay B2 so that the motor magnet MM continues to operate at this time. The closing of contact 400 of relay C2 extends ground to the second tens contact on the contact bank CB4. The respective relays are so constructed and their operation so timed that the counting relays will remove the ground from one tens contact and place it on the next contact before the wipers WI etc. can possibly reach the first tens contact.

The fourth and fifth dialing impulses cause the operation of the counting chain relays DI and D2 and El and E2 in the same manner, and the relay E2 will remain energized after the cessation of the dialing, and the fourth tens contact will be grounded. When the wiper W4 reaches the fourth tens contact, an energizing circuit is closed for the motor switching relay MSW. This relay is energized by current flowing from grounded battery through the resistance RA, through the lower Winding of relay MSW,

closed contact 50 ofv relay SWD, conductor 5|, wiper W4, conductor 52, alternate contact We of relay E2, conductor 53, through the winding of the sleeve control relay SCR, which also ener gizes, to ground. Relay MSW opens normal contact 43 to interrupt the circuit for the motor magnet MM, which accordingly is prevented from further operation at this time. 1

The closing of alternate contact 54 of relay MSW establishes an energizing circuit for the switching relay SWD which is energized by current flowing from grounded battery through the winding of relay SWD, alternate contact 54 of MSW, conductor 55, alternate contacts 33 v and 5901? relay OFA to ground. The relay SWD. v

locks itself up through its alternate contact 56 and closes a locking circuit for'therelay MSW at make-before-break contact 50. The opening of contact 25 of SWD removes thebattery from the energizing circuit of relays El andEZ'and 'these relays restore to normal and'remove ground from the fourth tens contact on bank CB4, and also open the energizing circuit of relay SCR.

In the-meantime, an energizing circuit for the ofi-normal relay. OFA has been closed at the off-normal contacts DNA, which assume their alternate position upon the first movement of the Wipers WI, etc. The dialing relay DR remains energized and itscontact 22 is in its alternate position, and therefore, the switching relay SW, which remained energized during the dialing of the first digit, falls back and closes its normal contact 51, which causes the energizaof relay SWA, normal closed contact 51 of SW, alternate contact 3| of relay IHR, conductor 32,

alternate contacts

33 and 59 of the off-normal relay OFA to ground. The relay SWA looks it- 'self up over the same circuit through its alter,-

The dial D' is moved in the usual way to interrupt the flow of current over the line circuit five times. The dialing relay DR responds di rectly to these interruptions and restores its contact 22 upon each interruption 'of the line. Upon the first restoration to-normal of contact 22 tion of the switching relay SWA by current flow- .ing from grounded battery through the winding of the relay DR, an energizing circuit for the'dial I hold-over relay DHO is established. -This relay is energized by current flowing from battery through the upper winding of relay DHO, conductor DC, alternate contact 23 of relay SWA to ground at normal contact 22 of relay DR. The closing of contact 10 of relay DI-IO completes an energizing circuit for the relay AI-IO; which may be traced from battery through the winding of relay AHO, alternate contact 10 of relay DHO, conductor 55,

alternate contacts

33 and 59 of relay OFA to the common ground CG. Relay AHO locks itself up through its alternate contact H tothe common ground CG. The relay. DHO is of slow-to-release construction and remains energized during the five interruptions of the line by the dial D. Each time the contact 22 of relay DR is restored to normal, the motor magnet MM is energized and deenergized to step the wipers WI, etc. This energizing circuit can be traced from grounded battery, alternate contact 42 of MSW, the winding of motor magnet MM, dialing conductor DCI, normal contact 62 of relay HCR, dialing conductor D02. alternate contact 43a of MSW, and dialing conductor DC to ground at alternate contact 22 of relay DR.

' After the last interruption contact 22 of relay DR remains in its alternate position and removes ground from the dialing'conductor DC, which causes the restoration of the relay DHO.

If the called line is idle If the called line, the multiple contacts of v DHO restores its contact 55. This relay is energized by current flowing from grounded battery through the winding of relay BTR, normal contact 63 of HCR, conductor 64, normal contact 65 of relay DI-IO, and alternate contact 66 of relay AHO, conductor 61, through the Winding of relay LCR to ground. The busy test relay BTR.

is not operated when an idle line is engaged by thewipers WI and W2, as the resistance of the relay LCR. is too high to permit the relay BTR to energize. The line control relay LCR closes its alternate contact 12 to place ground upon the wiper W2 for the purpose of busying this line against selection by another switch. Alternate contact 13 of LCR is closed to place ground upon the wiper W3 of this switch for busying purposes The closing of alternate contact I4 of relay LCR. disconnects the battery associated with relay BTR from the line and extends the line L to the wiper W! associated with contact bank CB2 and over the multiple connections to the contact bank CB5 associated with the called line. The sleeve relay SLR in the called line is energized by current flowing from grounded battery through the winding of sleeve relay SLR, conductor 14,, normal contact 15 of relay IHR of the called line circuit, conductor 16, contact T! of bank CB6 and its multiple connection to the contact bank CB2, wiper W2, conductor ill to ground at alternate contact '12 of relay LCR. The sleeve relay SLR in the calledline closes alternate contact l5 to connect the station on the called line in series connection with the called station. The operator will then restore the dial key DK to disconnect the dial D from the line. The operator at the calling station A will operate the meter key M to connect the meter into the line and the reading on the meter will inform the operator that the called station has been selected and the line is ready-for the transmission of the message. The series line connection can be traced from grounded battery DB through the resistance R, alternate contact 20 of the dial battery relay DBR, through the printer keys and operating magnets of the printer, the winding of polarized relays PLR. and PSR, normally closed contacts of release key RK and dial key DK, through the meter M, line L, the winding of relay DR, normal contact i5 of relay SLR of the calling line, line L, alternate contact E4 of relay LCR, line L, wiper Wl, contact bank CBI, and multiple connection, to contact bank CB5, alternate contact 55 of relay SLR of the called line, the winding of relay DR, line L, normal keys DK and RK, the winding of polarized start relay PSR, and the polarized line relay PLR, through the operating magnet and printer keys of the printer at the called station to normal contact 2!! and ground. The relay PSR. of the called line is operated by current flowing from battery at the calling station and closes its contact 2| to start the motor which drives the telegraph printer at the called station.

If the called Zinc is busy If the called line is busy, the engagement of the multiple contact associated with the called line by wiper W2 will permit the operation of the busy test relay BTR. The circuit for this relay can be traced from grounded battery through the winding of relay BTR, normal contact 63 of relay HCR, conductor 6 normal contact 65 of relay Dl-IO, alternate contact 66 of relay AHO, conductor 61, normal contact 13 of relay LCR, normal contact 79 'of relay HCA,

normal contacttd of relay SCR, conductor 8!,

, wiper W3, multiple contacts of the bank CB3 to the wiper W 3 or the previously connected line,

and conductor 8i, normal contacts 80 and 19, and alternate contact #3 of relay LCR of the other line, to ground. The line control relay LCR does not operate, because of the direct shunt, but the opening of contactl3 of relay BTR disconnects the battery return from the line L with the result that the polarized line relay PLR deenergizes for the release control relay RCR which is oper ated by current flowing from grounded battery through the winding of relay RCPJ, conductor 63 to ground at normal contact 3? of relay DHR.

' The release control relay RCR establishes a locking circuit for itself through its alternate contact conductor 32, alternate contacts 38 and 59 of relay OFA to the control ground CG.

The closing of alternate contact =29 establishes an energizing circuit for the release magnet RM which is energized by current flowing from grounded battery through the winding of RM, conductor 69, to ground at alternate contact 49 of relay RCR. The relay DHO is also energized by current flowing from grounded battery through the lower winding of relay DI-IO, conductor iii to ground at alternate contact 49 of relay R-CR. Relay DHO opens contact 65 to break the original energizing circuit of the busy test relay BTR. The operation of release magnet RM causes the wipers W! to WA to be restored to their normal position, and as soon as they are the oil-normal contacts ONA are opened to cause a deenergization of the off-normal relay OFA, which opens contact 59 to remove the control ground, which causes the deenergization of the release control relay RCR and the deenergization of relay 1% in Fig. 2 which closes contact 15 to render the line idle and permit the calling line to be connected to as a called line. Upon the restoration to normal of the dial key DK and the operation of the key M by the operator at station A the attendant will know that a busy line has been engaged because there will be no current flow and the reading on the meter wil1 indicate the opening of the line. In such a case it will be necessary for the attendant at station A to again dial the called station at a later time.

Operation when calledstatz'on 2's in first group If the desired called station terminates at the central exchange in the first group of contacts on the contact bank, the dialing number for that line will have the first digit 1 and the second digit will correspond to the location of that line in the group. p The operator at the calling station A will throw the dialing key DK to its alternate position to connect the dial D in a series connection with the line L and will there by cause the operation of the off-normal relay OFR, polarized relay PLR and the dialing relay DBR, which connects the dial battery DB to the line, through its alternate contact Hi to cause the operation of the polarized start relay PSR.

The operator next proceeds to dial the first digit,

which is l, on the dial which interrupts the energizing circuit of the. dialing relay DR. which v the winding of the polarized line relay PLR restores its contact 22 tonormal to close an energizing circuit for the switching relay SW and for the relayAl, as explained in conjunction with the former line connection, The relay II-IR is operated and opens contact 75 to render the selector and the calling line busy and prevent its selection by another selector as a called line.

The relay II-IR, of course,- locks itself up to ground at alternate" contact 31 of relayDI-IR.

Immediately upon the cessation of the dialing, impulse,.the first impulse relays Al and A2 are held operated through the substitute circuit previously described. The dialing relay DR is again energized andthe'switching relay SW accordingly restores to normal'to permit the energization of theswitching relay SWA which closes its alternate contact'fil to establish an energizing circuit for the switching relay SWD of Fig. 4;

which is energized by current flowing 1 from grounded battery through the windingof relay SWD, conductor 55, alternate contact tfi of relay A2, alternate contact-iii of relay SWA, and conductor 32 t'o'ground at alternate contact 31 of relay DHR I The relay SWD closes its alternate contact to establish an energizing circuit for the magnet switching relay MSW, which circuit can be traced from batterythrough the resistance RA, the lower winding of relay MSW, alternate contact 50 of relay SWD, the upper winding of. relay MSW to ground; The energization of relay MSW I I is completed.

causes the closing of alternate contact 22 to place the motor magnetdirectly under the control of the dial at station D. The operator atthe calling station then dials the second digit, which causes the motor magnet "MM to operateto step the wipers W1, etc, into connection with the contacts of the desired line, from whichitime the operation of this system is thesame as described in the connection to line 55.

I Disconnection 0 f line After the attendant has communicated with the called line and the connection is no longer desired, she will move the release key RK to its alternate position, thereby opening the line circuit to cause the deenergization of dial relay DR, which will open alternate contact 22 and cause the release of dialing relay DI-IR, which will close its normal contact 3l to causethe energization of the release 'control relay RCR.

The release control relay RCR energizes and closes its alternate contact 397 to establish an energizing circuit for the release magnet RM, which operates to restore the wipers WE, etcrto normal, at which time the contacts ONA are opened to dee'nergize the cit-normal relay 'OFA which disconnects the common ground CG and I permits the restoration to normal of all the operated apparatus at the central station. The

operation of the release key BK openedfthe locking circuit for the off-normal relay OFR which deenergized to. establish the shunt for which is deenergized and opens'its contact lfi to cause thedeenergization of the dial battery'- relay DBR which removes the dial battery-DB from the line.-

After a suitable time has elapsed the operator moves thekey RK to its normal position so that the line associated therewith willbe in condition for selection as a called line by another calling line. l

Hunting of idle Iii-ice in a desired group In telegraph printer systems a number of lines inayterminate at a single ofiice which is equipped with a telegraph printer for each line terminating therein. oftentimes another station may desire to be connected to a certain individual line at this office, in which case the operation of this system is the same as that described in connection with the selection of line 55. At other times toa certain individual station, but may be de- 'sirous of being connected to any line terminating at the ofiice. Provision has been made in my system whereby these lines terminate in. the contact bank in a certain group and whereby the selector switch is changed over from a driving orst'eppin'g operation to a hunting operation. When the wiper arms of the selector switch engage the first' contact of this group, the control of the switch is removed from the calling line and it proceeds to hunt for the first idle line in previously described. Then, however, the op-,

eratcr will dial the second digit, which in this case is 1, and as soon as the switch wipers engage the contact associated with line 5!, an energizing circuit for the group line relay GLR This circuit can be traced from grounded battery through the winding of relay GLR, wiper W3, conductor 86, normal contacts 39 and 19, normal contact 73of relay LCR,

through the winding of relay LCR to ground."

The'line control relay LCR' is not energized by current flowing over this circuit due to the resistance of the winding of the relay LCB. The

group linerelay GLR closes contact at to establish anenergizing circuit for the hunt control switching relays l-ICR and HCA. These relays are energized by current flowing from battery through the winding of the respective relays, normal contact'tl, conductor 88 to ground at alternate contact 86 of relay GLB. The relays I-ICR and HCA are locked up" through alternate contact 89 of relay HCR and alternate contact 960i relay OFA to the common ground CG. Following the single interruption of the line L, the dial hold-'overrelay DHO deenergizes and closes contact 85, but the busy test relay BTR cannot operate at this time due to the fact that its circuit has been opened at contact 63 of relay I-ICR;

If the contacts of the first line engaged by the selector switch wipers are busy, they will be at ground potential and an energizing circuit for the line hunting relay LI-IR will be closed. This circult can be traced from battery through the winding of relay LI-IR, conductor 9!, alternate contact 92 of OFA, alternate contact 36' of relay HC'A, conductor 45, normalcontact Al of motor magnet MM, alternate contact 33 of relay MSW,

conductor es, normal contact 94 ofrelay LI-IA, alternate contact it of relay HCA, normal COT-1',- tact all of relay HCR, conductor 1H,, wiper W3 to contact CB3 through the multiple connection to the busy selector switch,'through wiper W3 of the said'busy switch, its conductor 8|, normal closed contacts 3i! and F9 to ground at alternate contact E3 of the line control. relay ,LCR. in the busy switch or in certain instances to ground at alternateccntact 95 of relay LHAQ, LHR energizes'and at its'alternate contact 94 closes. an energizing circuit for the motor magnet MM,

' the calling station may not desire to be connected appended claims.

of single level switches atsaid central oflice, one

energized and causes the operation of the motor:

magnet MM. Each time the motor magnet M.M is energized, it opens its contact is to interrupt the energizing circuit for the relay LI-IR, which in turn interrupts the energizing circuit for the motor magnet MM, which deenergizes and steps its wipers Wl, etc.

This action takes place until the wiper W3 engages a contact leading to an idle line in the group. When this occurs there is no ground potential on the engaged contact and the shunt around the line hunting relay LEA is removed and the flow of current from the battery associated with relay LHR, is through the Winding of the relay LHA, which relay energizes and closes normal contact M to place a ground potential upon the contact bank CB3 associated with the wiper W3 to prevent the connection of another calling line to the line associated with the selector switch shoum. Relay LEA closes alternate contact all to place a ground potential upon the wiper W2 to again busy the selector switch and the line associated therewith. The closing of alternate contact 96 of relay LHA establishes an energizing circuit for the line control relay LCR, which relay is energized by current flowing from battery through the winding of relay BTR, alternate contact $3 of relay HOB, a tomato contact 96 of relay LHA, conductor 84, normal contact 65, alternate contact 65, conductor E'Lthrough the winding of relay LCR to ground. The relay BTR, as above explained, does not operate over this circuit due to its resistance. The line control relay LC'R closes its alternate contact M to'complete the line L so as to enable the connected stations to communi-, cats with each other. The subsequent disconnection is the same as previously described.

While I have described a preferred embodiment of, my invention, it is to be understood that modifications and changes will suggest themselves to those skilled in the art. I therefore desire to be limitedonly by the scope and spirit of the Having described my invention, what I claim is new and desire to secure by United States Letters Patent is:

rality of substations, a central office, lines joining said substations. to said central ofiice, a single level switch at said central office, wipers for said switch in which one oi said lines terminates contact terminals of the other of said lines in said switch arranged to be traversed by said wiper, said contacts being arranged in groups, means for moving said wiper to a desired group of contacts means for directively moving said wiper to a predetermined contact in said group and means acting incident thereto for causing said wiper to automatically seek a contact of an idle line.

2. A communication system including a plurality of substations, a central office, lines joining said substations to said central office, a plurality for each of said lines, contact terminals of said lines in said switches respectively, a wiper forv each switch in which its respective line terminates and arranged to traverse the contacts 1. A communication system including a pluthereof, said contacts being arranged in groups, means for moving, a wiper to a desired group of contacts, means for directively moving said wiper to a predetermined contact said group and means for thereupon causing said wiper to automatically seek a contact of an idle line.

3. A communication system including a plurality of substations, a central oifice, lines joining said substations to said central office, a plurality of single level switches, at said central ofilce, one for each of said lines, contact terminals of said lines in said switches respectively, a wiper for each switch in which its respective line terminates and arranged to traverse the contacts thereof, said contacts being arranged in'groups, a marking contact for each group of contacts, means for placing a distinguishing potential on the marking contact of a desiredgro'up, means for moving said wiper to the markingcontact having the distinguishing potential thereon, means for directively moving said wiper to a predetermined contact in said group and means for thereupon causing said wiper to automatically seek a contact of anidle line.

4. A communication system including a plurality of substations, a central office, lines joining said substations to said central office, a plurality of single level switches at said central office, one for each of said lines, contact terminalsof said lines in said switches respectively, a wiper for each switch in which its respective line terminates and arranged to traverse the contacts thereof, said contacts being arranged in groups, a marking contact for each group of contacts, a series of counting relays for placing a distinguishing potential on the'marking contact of a desired group of contacts, means for causing said wiper to automatically seek and select the marking contact having the distinguishing potential thereon, means for directively moving said wiper to a predetermined contact in said group and means for thereupon causing said wiper to automatically seek a contact of an idle line.

' 5. A communicating system including a plurality of telegraph lines, contacts arranged in all groups and connected to said lines, a group designating contact in each group, a group of counting relays adapted to mark respective designating contacts, a single level wiper associated with said contacts and means causing said wiper to hunt for and select the marked designating contact, and other means under the control of said lines for stepping said wiper to a selected predetermined contact in the group and for causing said wiper to then select a contact in the group connected to an idle line.-

6. A communicating system including a plurality of substations, a central station, lines extending between said substations and said. central station, dialing means at each of said substations, switching means at said central station for interconnecting any two lines under the control of the said dialing means, a source of current at said exchange normally connected to said line, polarized relays at said substation not responsive to current from said source, a source of current at said substation, relays responsive to said dialing means connecting said second source of current to said line to operate said polarized relays.

'7. A communicating system including a plurality of substations, a central station, lines extending from said substations to said central station, contacts at said central station arranged in groups and connected to said lines, a single level selecting wiper for each line associated with said scribers lines, a single series of contacts inwhich contacts for interconnecting any two of said lines, dialing means at the substations, counting relays at the central station responsive to'the' first operation of the dialing means to condition a group of said contacts, means for driving said wiper to said group of contacts, change over means for placing said operating means under the control of the subscribers line tostep said wiper to a certain selected contact in a groupv I and relay means causing said Wiper to seek a contact in said group connected to an idle line.

said contact for removing said wiper from said I dial control and causingit to hunt a contact connected to an idle line. v

9. A communicating system including a plurality of contacts connected to subscribers lines, a single level selecting wiper, said contacts being arranged in groups, means for associating said selecting wiper with a predetermined group of said contacts, other means for connecting':said selecting wiper to a predetermined contact of said predetermined group of contacts and third means for causingsaid wiper tohunt a contactconnected to an idle line in the group.

10. A communicatingsystem including aplurality of contacts connected to subscribers lines, a single level selecting wiper, said contacts be-, ing arranged in groups, means for operating said selecting wiper, relay means associated withsaid contacts for stopping said selecting wiper at a predetermined contact, change-over means for placing said operating means under the control of the subscribers line" to step said wiper to a certain selected contact ina group and other means causing said wiper to select a contact associated with an idle line. i

11. In a communicating system a group-of subscribers lines, a single series of contacts in which said lines terminateQsaid contacts'being divided intogroups, a contact of each' group being a marking contact, a switch having a wiper 'arranged to traverse the contacts of said series, substation controlled means arranged to place a distinguishing'potential on a desired one of said marking contacts and means for causing said wiper to hunt for the marking contact having the distinguishing potential thereon.

12. In a communicating system a group of subsaid lines terminate, said contacts being divided into .groups, a contact of each group being a I marking contact, a switch havinga wiper arranged to' traverse the contacts of said series,

substation controlled means arranged successively to place a distinguishing potential on said marking contacts and means for causing said wiper to hunt for the last marking" contact hav- "ing the distinguishing potential thereon. j

I 13, In a communicating system a group of subscribers lines, a single series of. contacts in which said linesterminate, said contacts being divided into groups, a contact of each group being a marking" contact, a switch having a wiper arranged to traverse the contacts of said series, substation controlled means arranged successiveand means for causing said wiper simultaneously .ly to place a distinguishing potential on said. marking contacts until, a desired one is reached 2 to hunt for the last marking contact having the distinguishing potential thereon.

14. In a communicating system a group of' subscribers lines, a single series of contacts in I Whichsaid lines terminate, said contacts being divided into groups, a contact of each group being a marking contact, a switch having a' wiper arranged to traverse the contacts of said series, a sending device, a series of counting relays controlled thereby arranged to place a distinguishing potential on a desired one of said.

marking contacts and means for causing said wiper to hunt for the markingcontact having the distinguishing potential thereon. I

15. In a communicating system a group of subscribers lines, contacts in which said lines-respectively terminate, said contacts being divided into groups, a-contact of each group being a marking contact, a switch having a wiper arranged to traversesaid contacts, substation controlled means arranged successively to place a distinguishing potential on said marking contacts and means for causing said wiper simultaneously to hunt for the last marking contact having the distinguishing potential thereon.

16. In a communicating system a group of sub scribers lines, contacts in which said lines respectively terminate, said contacts being divided into groups, there being a marking-contact for each group of contacts, a switch having a wiper arranged to traverse said, contacts, a sending device, a series of counting relays controlled there-,

by arranged successively to place a distinguishing r potential 'on said marking contacts and means for causing said wiper simultaneously to hunt.

ENN