US3508013A - Keyboard for telephone dialing utilizing impedance variation - Google Patents

Keyboard for telephone dialing utilizing impedance variation Download PDF

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Publication number
US3508013A
US3508013A US656879A US3508013DA US3508013A US 3508013 A US3508013 A US 3508013A US 656879 A US656879 A US 656879A US 3508013D A US3508013D A US 3508013DA US 3508013 A US3508013 A US 3508013A
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Prior art keywords
keyboard
resistance
key
column
contact
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Expired - Lifetime
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US656879A
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English (en)
Inventor
Claude Monin
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Alcatel CIT SA
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Alcatel CIT SA
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/26—Devices for calling a subscriber
    • H04M1/515—Devices for calling a subscriber by generating or selecting signals other than trains of pulses of similar shape, or signals other than currents of one or more different frequencies, e.g. generation of dc signals of alternating polarity, coded pulses or impedance dialling

Definitions

  • This invention relates to a keyboard device for dialing by impedance variation.
  • the combination of the two steps corresponds to the key depressed and the number of different combinations corresponds to the ten keys on the keyboard.
  • the signalling system is therefore determined by the different values given to the two resistances constituting the two groups. So that there is no ambiguity in the steps, the values of the resistances must lie within certain limits; in fact each resistance-diode may assume, for example, only one of four values either in one direction or other of the current.
  • the present invention relates more particularly to a general electromechanical keyboard arrangement adapted to be applied to the device described in the abovementioned French patent application.
  • One of the objects of the invention is to provide a strong and economical keyboard.
  • the keyboard device includes vertical driving bars and horizontal driving bars, one key actuating a vertical driving bar and a horizontal driving bar, each bar being adapted to close one working contact and position one resistance with respect to the lines.
  • the arrangement of the keys on the keyboard is such that the Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0 grouped in three rows of three keys and one row of one key situated in ice the middle column, extend from left to right and from top to bottom, the four rows corresponding to the four horizontal bars, each of which positions the resistances R to R respectively, and the three columns of the keyboard corresponding to the resistances R R and R respectively, only the key of numeral 9 having an individual contact and not acting on horizontal and vertical bars.
  • the keyboard arrangement in accordance with the invention may give the following code for the resistance combinations using resistances R R R and R corresponding to the ten figures of the keyboard:
  • the keyboard arrangement may be obtained by a permutation of the columns and/or the rows of the keyboard, the individual key being able to occupy any position.
  • the keyboard arrangement may be obtained by systematically combining the four horizontal resistances and the four vertical resistances.
  • One thus obtains a table of sixteen combinations, only ten of which are different, these being grouped in a triangle with a combination R R in the first column, two combinations R R and R R in the second column, three combinations R R R R and R R in the third column and four combina- IIIOIIS R1 R4, R2 R4, R3 R4 and R4 R4, in the fourth column, the arrangement of the keyboard being obtained by effecting the following permutations:
  • the third column is placed in the first position
  • the fourth column is placed in the second position
  • the second column is placed in the third position
  • the first column with only one combination is treated as a particular case and placed at the bottom of the third position.
  • FIGURE 1 shows a schematic diagram of the dialing circuit according to the above-mentioned French patent
  • FIGURE 2 is a diagram to aid the comprehension of the operation of the device according to FIGURE 1;
  • FIGURE 3 shows the combinations of possible resistances according to the invention
  • FIGURE 4 is one of the desired arrangements of the keyboard keys
  • FIGURE 5 shows a triangular keyboard arrangement in relation to FIGURE 3;
  • FIGURE 6 shows the changeover from the triangular arrangement according to FIGURE 3 to the arrangement desired according to FIGURE 4;
  • FIGURE 7 shows the general electro-mechanical diagram of the keyboard according to the invention.
  • the subscribers line is represented by dotted lines L L
  • the subscriber station is connected to the points A and B of the line while the exchange side is connected to the points A and B
  • working contacts t and t are made and a normally closed contact r is broken after making of the contacts t and t.
  • the current coming from the exchange passes through the contact t, a diode D and a resistance R; in a second stage of operation after reversal at the exchange, the current passes through the contact t, a diode D and a resistance R.
  • the combine receiver CO is in circuit when the keys of the keyboard are in the resting position.
  • change-over contacts I and I cause the reversal of the supply to the subscriber; they are controlled by a receiving device REC.
  • FIGURE 2 serves to explain the role played by the resistances inserted in the line when a key is depressed; the axis Ox thereof is graduated in milliamperes, for example.
  • the intensity of the line current determined by the impedance varies from to 1' according to the extent of the latter.
  • the intensity varies between two values according to the length of the line; for example, for the resistance R the line intensity may vary between i and i for the resistance R between i, and i etc.
  • i i corresponds the setting of a relay which thus detects the resistance R inserted; as two successive current steps are carried out, one direct and the other reversed, two relays are finally set olf which, according to a code, correspond to the figure whose key has been depressed and which is communicated to the recording device.
  • FIGURE 3 is a table showing in a known manner the various possible resistance combinations derived from resistances R R R and R
  • the vertical column shows for example the values R to R, which may be assumed by the resistance R of FIGURE 1,, and the rows across give the values R and R; that can be assumed by the resistance R of FIGURE 1.
  • FIGURE 4 shows a keyboard arrangement which it is desired to obtain; there are. four rows and three columns.
  • the first row are the figures 1, 2 and 3; in the second row, the figures 4, 5 and 6; in the third row there are the figures 7, 8 and 9 and in the fourth row, at the bottom of the middle column, the figure 0.
  • the general form of the combinations is thus very different from the triangular form of FIGURE 3.
  • FIGURE 5 placing the keys corresponding to the combinations, FIGURE 5 is obtained; there is one column with one key associated with the resistance R a column with two keys associated with the resistance R a column with three keys associated with the resistance R and a column with four keys associated with the resistance R it is the same for each horizontal row but a row of four keys is associated with the resistance R a row of three keys with the resistance R etc.
  • the known triangular arrangement is thus obtained.
  • FIGURE 6 shows how one obtains the desired keyboard arrangement given in FIGURE 4, starting from FIGURE 5.
  • the third column of FIG- URE 5 is placed in the first position, the fourth column in the second position and the second column in the third position; the first column with a single key is treated as a particular case: The corresponding key is placed below the two key column and is provided with an individual contact.
  • a unique association of two resistances R and R corresponds to each key of the keyboard, the first controlled by the horizontal bar R and 4 the second controlled by the vertical bar R
  • the following code results for the ten figures of the keyboard.
  • FIGURE 7 is the e-lectro-mechnnical diagram of the keyboard according to the invention.
  • the keyboard comprises horizontal bars H H H and H and vertical bars V V and V which may be spring loaded in the wellknown manner.
  • Each key 1, 2, 3, 4, 5, 6, 7, 8, 0 controls movement of a vertical bar and a horizontal bar, each vertical bar closing a respective contact t t t and each horizontal bar closing a respective contact t' t t t'.,.
  • the horizontal bars may be positioned above the vertical bars, as seen in the figure, or vise versa, with the key stems (not shown) engaging the bars to effect longitudinal movement thereof upon depression of a key to close a corresponding switch. As each contact closes, it connects a resistance R R R or R in the line.
  • the line A is likewise connected to the contact t through a resistance R to the contact t through a resistance R to the contact t' through a resistance R to the contact t through a resistance R
  • the line B is connected to the contacts t t 2' t' mounted in parallel through a diode D, and to the contacts 1 t t mounted in parallel through a diode D.
  • the circuit is made as follows: Wire A, resistance R contact t diode D and wire B for the first step of operation; as the second step of operation takes place after reversal of the line current, that is to say with positive polarity at B and negative polarity at A, the circuit is made via: Wire B, diode D, contact t resistance R and wire A.
  • the resting contract r is in a known manner actuated by the group of horizontal bars and by the key 9; this contact is opened after closing of the working contacts and has 'as its function to put the receiver out of circuit during the operation of a key.
  • the individual key may occupy another position on the keyboard; for example, if may be placed in another column or in another row.
  • the invention is not limited to the permutation given by way of example above; any other permutation may be used. For example, i
  • the second column may be placed in the first position, the fourth column in the second position, the third column in the third position, the individual key being placed at the bottom or at the top of the second column in the first position.
  • the fourth column is preferably placed in the middle.
  • a keyboard device for dialing by impedance variation in which the act of operating any key on the keyboard causes on the one hand the positioning of two resistances connected to respective rectifier elements poled in opposite directions across first and second line-wires and on the other hand the disconnection of the station from the circuit, the identification of the key depressed taking place at the exchange through two successive measurements of the line current, one with direct supply voltage of one polarity and the other with reverse polarity supply voltage, corresponding to the two resistances connected in circuit, wherein the device comprises:
  • each driving bar serving to connect one resistance across the line wires upon actuation of the switch associated therewith.
  • keyboard arrangement is obtained by a permutation of the columns and rows of driving bars of the keyboard.
  • keyboard arrangement is obtained by systematically combining the four horizontal resistances and the four vertical resistances, thus obtaining a table of sixteen combinations, ten different combinations of which being assigned to the indivdiual keys, these being grouped in a triangle with a combination R R in a first vertical line, two combinations R R and R R in a second vertical line, three combinations R R R R and R R in a third vertical line and four combinations R R R R R R and R R in a fourth vertical line, the arrangement of the keyboard being obtained by effecting the following permutations:
  • the third vertical line is placed as the first column
  • the fourth vertical line is placed as the second column
  • the second vertical line is placed as the third column
  • the first vertical line with only one combination is treated as a particular case and placed at the bottom of the third column.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Input From Keyboards Or The Like (AREA)
US656879A 1966-07-29 1967-07-28 Keyboard for telephone dialing utilizing impedance variation Expired - Lifetime US3508013A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR71558A FR1525030A (fr) 1966-07-29 1966-07-29 Disposition de clavier pour numérotation par variations d'impédance

Publications (1)

Publication Number Publication Date
US3508013A true US3508013A (en) 1970-04-21

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ID=8614519

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US656879A Expired - Lifetime US3508013A (en) 1966-07-29 1967-07-28 Keyboard for telephone dialing utilizing impedance variation

Country Status (8)

Country Link
US (1) US3508013A (fr)
BE (1) BE701754A (fr)
CH (1) CH476432A (fr)
DE (1) DE1537746A1 (fr)
FR (1) FR1525030A (fr)
GB (1) GB1195399A (fr)
LU (1) LU54185A1 (fr)
NL (1) NL6709457A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3665489A (en) * 1969-06-06 1972-05-23 Ericsson Telefon Ab L M Telephone instrument for voice frequency choice of number
US4502040A (en) * 1981-06-23 1985-02-26 Renix Electronique Keyboard having keys activated by electrical contacts and the capacity to read one state from among four possible states
US20070290889A1 (en) * 2006-06-20 2007-12-20 Qualcomm Incorporated Two-Wire Connection to a Key Matrix in a Mobile Device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2927971A (en) * 1957-12-30 1960-03-08 Bell Telephone Labor Inc Subscriber call transmitting system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2927971A (en) * 1957-12-30 1960-03-08 Bell Telephone Labor Inc Subscriber call transmitting system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3665489A (en) * 1969-06-06 1972-05-23 Ericsson Telefon Ab L M Telephone instrument for voice frequency choice of number
US4502040A (en) * 1981-06-23 1985-02-26 Renix Electronique Keyboard having keys activated by electrical contacts and the capacity to read one state from among four possible states
US20070290889A1 (en) * 2006-06-20 2007-12-20 Qualcomm Incorporated Two-Wire Connection to a Key Matrix in a Mobile Device
WO2007149872A2 (fr) * 2006-06-20 2007-12-27 Qualcomm Incorporated Connexion bifilaire vers une matrice de touches dans un dispositif mobile
WO2007149872A3 (fr) * 2006-06-20 2008-04-17 Qualcomm Inc Connexion bifilaire vers une matrice de touches dans un dispositif mobile
US8471733B2 (en) 2006-06-20 2013-06-25 Qualcomm Incorporated Two-wire connection to a key matrix in a mobile device

Also Published As

Publication number Publication date
DE1537746A1 (de) 1969-10-16
NL6709457A (fr) 1968-01-30
BE701754A (fr) 1968-01-24
FR1525030A (fr) 1968-05-17
GB1195399A (en) 1970-06-17
LU54185A1 (fr) 1969-05-21
CH476432A (fr) 1969-07-31

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