US1972985A - Electric switching device - Google Patents

Electric switching device Download PDF

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US1972985A
US1972985A US483880A US48388030A US1972985A US 1972985 A US1972985 A US 1972985A US 483880 A US483880 A US 483880A US 48388030 A US48388030 A US 48388030A US 1972985 A US1972985 A US 1972985A
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keys
key
operated
stock
path
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US483880A
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Leland A Gardner
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AT&T Corp
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American Telephone and Telegraph Co Inc
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00Data switching networks
    • H04L12/02Details
    • H04L12/06Answer-back mechanisms or circuits

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  • This invention relates to communication systems and more partlcularly to printlng telegraph automatic exchange systems wherein intelligence ci a changeable nature 13 stored by means of 23 manually operatlng a series of locklng ke.vs foi g@ operated keys in a looked the purpose of automatieally transmittlng the latest intelligence to semote points whenever clesireol.
  • An object of the invention is to malntain the position by electxlcal meams.
  • Anothei object ls to release the operaterl keys eleotrlcally whenever more than the desired mim ber oi l;eys are operated in any one column of keys or any one group of keys.
  • keys such as those used in com municatiom systems, have been provided with loclcing features which were obtained by means oi slldlng plates fixeci to the key trame by means of retractlle sprlngs.
  • Whfle a key is seing movel to its operateci position, the plate 15 moved in suoh a. manner that when the key-reaches lts final operated position, the plate springs back to its normal position, ther by locking the key in its operated position.
  • the operation of a second key again moves the'plate, permittlng the rst key to retum t normal and the second key le thon looked when theplate returns to normal.
  • Patent 1,948,969 grantecl to C. C. Lame on Feloruary 27, 1934.
  • One side of aillerr is adapted to so gage a pair of contact springs which are arrangeci, when operated, to cuit for an electromagnet which, when impulsecl, attracts the other side oi. the plunger to thereioy hold the key in an operatecl position.
  • N115 in ventien is particularly adapted to a stock quotation automatlc telegraph exchaoge wherein tlze keys are employed for setting up in a sterlng devise the latest quotaticn of any one stock, a separate set being provided for each stock listed on the eschange.
  • provision is marie for the automatlc reiease of all operated keys wlaen more than thedesired number of keys are oper ated.
  • the maximum number of characters in a stock quotatlon are usually four coniprising hunclres, tons, units and tractions and when more than four keys are operated the circuits for the energized holding magnets are automatlcally opened to release the operated keye.
  • nother ieature is the immediate releaee by electrieal means 01 en operated key slzculc.
  • Tne drawing illustrates a set of stock quotatlon lzeys whlch, when operated, are arranged to close contacts oves whloh are transmitted codeimpules corresoonding to the digits 0 to 9 and fractions to the latter varylng in incrememts of
  • the arrangement shown inthe drawing provides means whereby outlying' stock brokers ofces equipped with tape telegraph typewrlter prlnters woulcl be able, by sending the symbols of a certain stock to the stock exchange, to receive thereirom automatlcally the last sale priee, whieh would be printed on the tape et the brokers mintes immedlately following the symbols of the stock :for which the recluest was made.
  • Thls lest sale prise would be stock exchange zoo5t opeator and the system le arranged tl2at request incoming 'r0m brokers ofilees would aut0matlcally arrive at the point eontainng titis lest sale price, From this point the last recorded prlce quotatlon would be sent. in response to eve2:y such sequest untfl changed les; the post operator.
  • the post opeiator wold be iumlshed with a set or bt-31k o l:eys
  • the zey set shown in the drawing is adapted to operate with a storing and sending meehanlsm of tloe rotary distributor type.
  • the rotary distributor arrangement is described in detail in the applicamts oopendlng application, Serial No. 564, 940, filed September 24, 1931.
  • the storing and sendfmg arrangement ls designed to transmit foi eaeo chaeaoter seven impulses of thestart-stop flve unit code, consistlng 02 the start and the stop impulses and the live signal impulsee.
  • the accompmylng drawing shows tloe arrangementpreflerably adapted for the automatlc stock quotation system disclosd in the applicants copending application, supra. wherein the rotary olistributor sonder arrangement 1s emxfioyed.
  • each set of keys is provided at a trading post on the fioor 01 the exchange for each stock handled at that post.
  • Each one of the quotation keys and the .send key would have associated with it a set et contacts and a holding coil which would be' sufiiciently ener- 'gized at the time the key is depressed to hold the lrey in its operated position. The key would remain operated until the holding circuit through the key contacts and the holding magnet is opned as will ibe hereinafter described.
  • the send keyl6 when operated, is similarly locled, but through a circuit extending from ground through the closed contact 01 lrey 1.6, through the windings of holding magnet 21 and etc. and each key is connected to its distributor r,ora,oss
  • the outer left hand contact sets of the operated keys 12, 13, 14 and 15 are cash arranged to continually receive a combination of start-stop 1ive unit code impulses corresponding to the digits or fractions represented by these keys and v
  • the "send key 16 is depressed to its operated position the combinations oi impulses received over each of the operated keys, 12, 13, 14 and 15 are transmitted, in turn, through the loft hand contact set of key 16 to the conductor 11, the sequence of the combination, that is, in the hundrcds, tens, suns and fractions places, being eilected by the arrangement of the hundreds, tons, units and fractions groups of segments on the distributor sonder device (not shown) but described in detail in the applicants copending application, supra.
  • any nnoperated key may be operated to efiect the operation of relay E, whereby all operated keys lii are released.
  • Means may be provided With each key set -for indicating to the opcrator at a post the moment when the transmission of a quotation is completed so that ne may the'n make the change in 3213 the key set.- As 'Stated ahove and described in thecopending application, supra, the distributor sentier is continually sending qotations over the Iet-hand closed contact sets of the operated keys, 325 and between successive quotations the distributor transmits space or wai impulses. '1he post operator may select the hait second interval of the "wait" impulse as being desirable to efiect the che in the key setting, thereby avoiding gfi) a change (1 the transmission of a quotation.
  • Tire indication means may be a signal lamp (net shown) tout provided at each key set and aed tu ne operated by the wait impulse whereby the operxitor will hou; when the quota- 1188 tian is completed.
  • Tire hundreds keys form a set 02 elements cor- 11 to the hundreds denotion, the a set 02 elements to the tons denomimtion, g
  • each of said sets of elements comprising a manually operable key, a pair of normally opened contact sets responsive to the operation 01 said key, a circuit including one of said contact sets and a magnet, when energized, for holding each key when operated, in an operated position, said circuit including a path common t0 ail the circuits of its group, a path common to all said circuits of all said groups, and a source of current connected to the second mentioned path, and a connecti0n including the other of said contact sets, said connecticn including a third path common to all said other connections of its group and an outgoing path common to all said other connections of all said groups, means in said outgoing path for completing said third path when one or more keys are held in their operated positions by their errergized magnets, means connected n each of the first mentioned paths for releasing the keys held in operated positions when more than one key in the group are operated, and other means connected in the second mentioned path for releasing
  • a switchng syste-m a plurality of manually operated keys arranged in groups, a holding magnet for each of said keys, a normally opened operating circuit for each of said magnets, said circuits including a normally closed path common to the operating circuits of the magnets of' each group, and a second normally closed path common to all the first mentioned normally closed paths, a source of current connected to said second path, means in engageable relation with each of said keys for completng the operating circuit for the associated magnet in response to the operation of said key, a circuit-breaking de- 8. plurality o1 electromagnets respectively associated with said keys for locking their respectively associated keys in operated positions, a
  • an additional electromagnet and an armature thereof in each of said operating circuits for releasing a1l operated keys in a group when more than one key in the group are in operated positions, an incoming path connected through the other of said sets 01 contact springs on each of said keys, an additional manually operated double plunger key, an eiectromagnct and an operating circuit therefor for locking said additional key in its operated position, said operating circuit for the last mentioned electromagnet being connected to the flrst mentioned operating circuit to form a common path, a single outgoing path for said incoming path, a pair of normally opened contact spring sets on said additional key, one of the last mentioned sets responsive to the operation of said additional key for connecting one or more of the incoming paths respectively closed by one or more of the operated keys in different groups to said single outgoing path, and the other of the last mentioned sets being responsive to the operation 01 said additional key for completing the operating circuit of the iast mentioned electromagnet, and an additional electromagnet and an armature threfor in

Description

Patented Sept. 11, 1934 PATENT OFFICE 1,972Q935 omomo swmomo mmos American Telephone corporation of New assigner to Compamy, a
Application Seotemlr a3, 1930, Serin! No; 483,880 4 Claims. o1. 177 380) This invention relates to communication systems and more partlcularly to printlng telegraph automatic exchange systems wherein intelligence ci a changeable nature 13 stored by means of 23 manually operatlng a series of locklng ke.vs foi g@ operated keys in a looked the purpose of automatieally transmittlng the latest intelligence to semote points whenever clesireol.
An object of the invention is to malntain the position by electxlcal meams.
Anothei object ls to release the operaterl keys eleotrlcally whenever more than the desired mim= ber oi l;eys are operated in any one column of keys or any one group of keys.
Heretofore, keys, such as those used in com municatiom systems, have been provided with loclcing features which were obtained by means oi slldlng plates fixeci to the key trame by means of retractlle sprlngs. Whfle a key is seing movel to its operateci position, the plate 15 moved in suoh a. manner that when the key-reaches lts final operated position, the plate springs back to its normal position, ther by locking the key in its operated position. The operation of a second key again moves the'plate, permittlng the rst key to retum t normal and the second key le thon looked when theplate returns to normal. Such an arrangement is disclosed in Patent 1,948,969 grantecl to C. C. Lame on Feloruary 27, 1934.
Aocordlng to the present invention the lses are of the push butter; type having inverted lJ-=shaped plunger5. One side of a plonger is adapted to so gage a pair of contact springs which are arrangeci, when operated, to cuit for an electromagnet which, when energiaecl, attracts the other side oi. the plunger to thereioy hold the key in an operatecl position. N115 in ventien is particularly adapted to a stock quotation automatlc telegraph exchaoge wherein tlze keys are employed for setting up in a sterlng devise the latest quotaticn of any one stock, a separate set being provided for each stock listed on the eschange. In the present invention provision is marie for the automatlc reiease of all operated keys wlaen more than thedesired number of keys are oper= ated. For example, the maximum number of characters in a stock quotatlon are usually four coniprising hunclres, tons, units and tractions and when more than four keys are operated the circuits for the energized holding magnets are automatlcally opened to release the operated keye.
nother ieature is the immediate releaee by electrieal means 01 en operated key slzculc. a
aslzel quotatlon system would conslst close an operating oir-= second key in one columxa, that is, in the hundreds. tons, units or fractions column be operated.
Other objects and features will be found in the following description and appended claims when taken in conjonction with the cirawimg. v
Tne drawing illustrates a set of stock quotatlon lzeys whlch, when operated, are arranged to close contacts oves whloh are transmitted codeimpules corresoonding to the digits 0 to 9 and fractions to the latter varylng in incrememts of The arrangement shown inthe drawing provides means whereby outlying' stock brokers ofces equipped with tape telegraph typewrlter prlnters woulcl be able, by sending the symbols of a certain stock to the stock exchange, to receive thereirom automatlcally the last sale priee, whieh would be printed on the tape et the brokers mintes immedlately following the symbols of the stock :for which the recluest was made. Thls lest sale prise would be stock exchange zoo5t opeator and the system le arranged tl2at request incoming 'r0m brokers ofilees would aut0matlcally arrive at the point eontainng titis lest sale price, From this point the last recorded prlce quotatlon would be sent. in response to eve2:y such sequest untfl changed les; the post operator.
The post opeiator wold be iumlshed with a set or bt-31k o l:eys
for each stock loanolled at any one post and by the manipulation ci these keys, he would keep the storingox sending mecl1anism supplied with the last sale prlce oi. the stock to which the key set 15 asslgned. A bic! and of a dupll cote set of keys and senders, one set for laid price and (me set for asked prlce.
The zey set shown in the drawing is adapted to operate with a storing and sending meehanlsm of tloe rotary distributor type. The rotary distributor arrangement is described in detail in the applicamts oopendlng application, Serial No. 564, 940, filed September 24, 1931. The storing and sendfmg arrangement ls designed to transmit foi eaeo chaeaoter seven impulses of thestart-stop flve unit code, consistlng 02 the start and the stop impulses and the live signal impulsee. These a1- mngements may also loe designed to transmit by means of a six'unlt code by ehanglng th trans-= mitting elements of each accordflngly.
The accompmylng drawing shows tloe arrangementpreflerably adapted for the automatlc stock quotation system disclosd in the applicants copending application, supra. wherein the rotary olistributor sonder arrangement 1s emxfioyed.
stored in a mechanism by a Only so much of the aLpparatus is shown as will give a clear understanding of the invention. A
set of keys is provided at a trading post on the fioor 01 the exchange for each stock handled at that post. There are in each set 38 keys arranged in four rows, A, B, C, and D, namely, hundreds, tons, units and fractions, respectively, and in each of rows A, B, and C there are ten keys corresponding to the digits to 9 and in row D there are 7 keys corresponding to the fractions to /a varying in increments o'f and one key cailed a send" key. for connecting all the keysin operated condition to the conductor 11 which is included in the operating.circuit for a series of sonder relays which reprodiwe the information for a series of transmitting points at which it is available to a plurality oi calling, or brokers, limes. The circuit including cbnductor 11 and its lunction are described in the applicants copending application, supra. The post operator would note the last sale price and set up the combination on the qu0tation keys, after Which he Would press the "send key, thus making the price available for any subsequent request incoming from a brokers ofiice. Each one of the quotation keys and the .send key would have associated with it a set et contacts and a holding coil which would be' sufiiciently ener- 'gized at the time the key is depressed to hold the lrey in its operated position. The key would remain operated until the holding circuit through the key contacts and the holding magnet is opned as will ibe hereinafter described.
These columns or rows of keys have connected in series in the holding circuits thereof a marginal slow release relay adjusted to operate on a current drain of more than one lrey holding coil. There' fore, in case two quotation keys in any one column are depressed it would be impossible to keep the second one operatcd and the flrst one would return to normal. These marginal relays A to D inclusive are respectively connected to the quotation keys in the four rows A to D inclusive. A marginal relay E, also of the slow release type isone Which will operate on a current drain of slightly more than five keys including the send key, and would retum all keys to normal in case the operator should make an error b trying to set up a combination of more than iive lreys foi a quotation of any one stock. Tire slow release l'eaturc of those marginal relays will allow the magnetic circuit of the holding' colis to be completely deenergized before the relays return to normal wherein the holding or locking circuits are again prepared for a new i:ey setting.
Let it be assumed that the last sale price or quotation on any certain stock is 209%. The post.
operator will depress keys 12, 13, 14 and 15 and snd lsey 16. The operation of key 12 immediately closes at the right hand contacts 01 the key an operating circuit for holding magnat 17 Which may be traced from ground at key 12, through 1 the Windings cf holding niagnet. 17, rela A and inlay E, in series, armature and contact o relay E to grounded battery. Rclays A and E being of the marginal type do not operate but magnat 17 dues, that is, energizes sufiiciently to hold hey 12 in an operated or depressed position. Tire operation.of keys 13, 14 and 15 will like energize holding magnets 18, 19 and 20 respectiveiy,
through their associated marginal relays B, C and D. The send keyl6, when operated, is similarly locled, but through a circuit extending from ground through the closed contact 01 lrey 1.6, through the windings of holding magnet 21 and etc. and each key is connected to its distributor r,ora,oss
marginal relay E. in series, armature and contact of relay E to grounded battery.
The outer left hand contact sets of the operated keys 12, 13, 14 and 15 are cash arranged to continually receive a combination of start-stop 1ive unit code impulses corresponding to the digits or fractions represented by these keys and v When the "send key 16 is depressed to its operated position the combinations oi impulses received over each of the operated keys, 12, 13, 14 and 15 are transmitted, in turn, through the loft hand contact set of key 16 to the conductor 11, the sequence of the combination, that is, in the hundrcds, tens, nuits and fractions places, being eilected by the arrangement of the hundreds, tons, units and fractions groups of segments on the distributor sonder device (not shown) but described in detail in the applicants copending application, supra.
' Should the operator by mistake operate two ireys in column or row A, the current drain through the wind ings of the associated holding magnets will be sufiicient to operate relay A and to thereby open the energizing circuit for the magnets. Should the relay A in response to the operation of two keys in row A, fail to operate, there will be, when send key 16 is e'ventuaily operated, six magnets, two in row A and one each in rows B, C, and D and the one associated with the send key, energized, and the current drain 1 through the six magnets will be sufiicient to operate relay E which opens the energizing circuits through all the energzed magnets, and the operated keys will be returned to normal because of the tension inthe c011 springs such as those E designated 22, 23 etc. on the key shafts.
Should it be desired to change the key setting because of a change in the sale price of the stock any nnoperated key may be operated to efiect the operation of relay E, whereby all operated keys lii are released.
Means may be provided With each key set -for indicating to the opcrator at a post the moment when the transmission of a quotation is completed so that ne may the'n make the change in 3213 the key set.- As 'Stated ahove and described in thecopending application, supra, the distributor sentier is continually sending qotations over the Iet-hand closed contact sets of the operated keys, 325 and between successive quotations the distributor transmits space or wai impulses. '1he post operator may select the hait second interval of the "wait" impulse as being desirable to efiect the che in the key setting, thereby avoiding gfi) a change (1 the transmission of a quotation. Tire indication means may be a signal lamp (net shown) tout provided at each key set and aed tu ne operated by the wait impulse whereby the operxitor will hou; when the quota- 1188 tian is completed.
Tire hundreds keys form a set 02 elements cor- 11 to the hundreds denotion, the a set 02 elements to the tons denomimtion, g
segment whicid forme a sonder of a code combinatlon corresponding to its deno tien and particular charater of that denoation.
. La la claim9d in: 2 fi 1% l. In a switching system, a pluralit jp uaily operated lzeys dispcsed in rows; m individual to each iizey i"or magnetically locling said l:ey in an operated position, means individual to each of said rbas for rend 2::
ineiective the 1541 locking means in said each of said rows when more than one key in said each of said rows are in operated positions, and means common to all said rows for rendering inefiective the magnetic locking means of all said rows when the total number of operated keys exceeds the number of rows of keys.
2. In combination, a plurality of sets of elements, said sets being arranged in groups, each of said sets of elements comprising a manually operable key, a pair of normally opened contact sets responsive to the operation 01 said key, a circuit including one of said contact sets and a magnet, when energized, for holding each key when operated, in an operated position, said circuit including a path common t0 ail the circuits of its group, a path common to all said circuits of all said groups, and a source of current connected to the second mentioned path, and a connecti0n including the other of said contact sets, said connecticn including a third path common to all said other connections of its group and an outgoing path common to all said other connections of all said groups, means in said outgoing path for completing said third path when one or more keys are held in their operated positions by their errergized magnets, means connected n each of the first mentioned paths for releasing the keys held in operated positions when more than one key in the group are operated, and other means connected in the second mentioned path for releasing the keys held in operated positions when the number of keys operated exceeds the number of groups of eiement sets.
3. In a switchng syste-m, a plurality of manually operated keys arranged in groups, a holding magnet for each of said keys, a normally opened operating circuit for each of said magnets, said circuits including a normally closed path common to the operating circuits of the magnets of' each group, and a second normally closed path common to all the first mentioned normally closed paths, a source of current connected to said second path, means in engageable relation with each of said keys for completng the operating circuit for the associated magnet in response to the operation of said key, a circuit-breaking de- 8. plurality o1 electromagnets respectively associated with said keys for locking their respectively associated keys in operated positions, a
pair of normally opened contact spring sets on one of the plungers of each of said keys, a source of potential, an operatng circuit connected to said source. in which the electromagnets of each group of keys are respectivcly connected in parallel paths, each path including one of said sets of contact springs. an additional electromagnet and an armature thereof in each of said operating circuits for releasing a1l operated keys in a group when more than one key in the group are in operated positions, an incoming path connected through the other of said sets 01 contact springs on each of said keys, an additional manually operated double plunger key, an eiectromagnct and an operating circuit therefor for locking said additional key in its operated position, said operating circuit for the last mentioned electromagnet being connected to the flrst mentioned operating circuit to form a common path, a single outgoing path for said incoming path, a pair of normally opened contact spring sets on said additional key, one of the last mentioned sets responsive to the operation of said additional key for connecting one or more of the incoming paths respectively closed by one or more of the operated keys in different groups to said single outgoing path, and the other of the last mentioned sets being responsive to the operation 01 said additional key for completing the operating circuit of the iast mentioned electromagnet, and an additional electromagnet and an armature threfor in said common path for releasing ail operated keys when the total number of operated keys exceeds the number of groups of keys.
LELAND A. GARDNER.
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Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2425974A (en) * 1940-06-26 1947-08-19 Seeburg J P Corp Automatic phonograph
US2437712A (en) * 1946-02-15 1948-03-16 Malcolm H Sheldon Electrical control system
US2451150A (en) * 1944-06-02 1948-10-12 Rca Corp Radio remote-control system
US2468112A (en) * 1944-08-29 1949-04-26 Rosen Leo Counting apparatus
US2484226A (en) * 1947-10-17 1949-10-11 Bell Telephone Labor Inc Indicating circuit
US2505566A (en) * 1945-07-23 1950-04-25 Bell Telephone Labor Inc Signaling system
US2550600A (en) * 1948-11-22 1951-04-24 Bell Telephone Labor Inc Indicating circuit
US2570481A (en) * 1946-09-28 1951-10-09 Guardian Electric Mfg Co Switch construction
US2609433A (en) * 1947-05-28 1952-09-02 Bell Telephone Labor Inc Perforating recorder signaling device
US2691342A (en) * 1954-10-12 Johnston etaj
US2724104A (en) * 1954-10-06 1955-11-15 Ibm Ring check circuit
US2737647A (en) * 1952-10-25 1956-03-06 Monroe Calculating Machine Keyboard alarm
US2769971A (en) * 1954-10-04 1956-11-06 Ibm Ring checking circuit
US2838115A (en) * 1955-12-14 1958-06-10 Ibm Multiple punch prevention device
US2856130A (en) * 1954-06-29 1958-10-14 Underwood Corp Printing input and output device for a computer
US2900447A (en) * 1953-09-24 1959-08-18 Siemens Ag Apparatus for correcting the effects of disturbances in telegraphic communication
US3027071A (en) * 1958-12-26 1962-03-27 A Kimball Co Record analyzing apparatus
US3240427A (en) * 1962-06-11 1966-03-15 Jimmie L Holman Keyboard method, apparatus and system for data transmission
US3248724A (en) * 1960-08-05 1966-04-26 Bell Telephone Labor Inc Plural order digit display apparatus
DE1290569B (en) * 1965-11-15 1969-03-13 Western Electric Co Mechanically operated button for a keypad transmitter with a magnetically responsive contact set, especially for teleprinters

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691342A (en) * 1954-10-12 Johnston etaj
US2425974A (en) * 1940-06-26 1947-08-19 Seeburg J P Corp Automatic phonograph
US2451150A (en) * 1944-06-02 1948-10-12 Rca Corp Radio remote-control system
US2468112A (en) * 1944-08-29 1949-04-26 Rosen Leo Counting apparatus
US2505566A (en) * 1945-07-23 1950-04-25 Bell Telephone Labor Inc Signaling system
US2437712A (en) * 1946-02-15 1948-03-16 Malcolm H Sheldon Electrical control system
US2570481A (en) * 1946-09-28 1951-10-09 Guardian Electric Mfg Co Switch construction
US2609433A (en) * 1947-05-28 1952-09-02 Bell Telephone Labor Inc Perforating recorder signaling device
US2484226A (en) * 1947-10-17 1949-10-11 Bell Telephone Labor Inc Indicating circuit
US2550600A (en) * 1948-11-22 1951-04-24 Bell Telephone Labor Inc Indicating circuit
US2737647A (en) * 1952-10-25 1956-03-06 Monroe Calculating Machine Keyboard alarm
US2900447A (en) * 1953-09-24 1959-08-18 Siemens Ag Apparatus for correcting the effects of disturbances in telegraphic communication
US2856130A (en) * 1954-06-29 1958-10-14 Underwood Corp Printing input and output device for a computer
US2769971A (en) * 1954-10-04 1956-11-06 Ibm Ring checking circuit
US2724104A (en) * 1954-10-06 1955-11-15 Ibm Ring check circuit
US2838115A (en) * 1955-12-14 1958-06-10 Ibm Multiple punch prevention device
US3027071A (en) * 1958-12-26 1962-03-27 A Kimball Co Record analyzing apparatus
US3248724A (en) * 1960-08-05 1966-04-26 Bell Telephone Labor Inc Plural order digit display apparatus
US3240427A (en) * 1962-06-11 1966-03-15 Jimmie L Holman Keyboard method, apparatus and system for data transmission
DE1290569B (en) * 1965-11-15 1969-03-13 Western Electric Co Mechanically operated button for a keypad transmitter with a magnetically responsive contact set, especially for teleprinters
DE1290569C2 (en) * 1965-11-15 1974-05-30 Western Electric Co MECHANICALLY OPERATED BUTTON FOR A KEYPAD TRANSMITTER WITH A MAGNETICALLY RESPONDING CONTACT SET, IN PARTICULAR FOR TELEPHONE DEVICES

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