DE2345757A1 - DEVICE FOR TRANSMITTING TELEPHONE NUMBERS WITH THE HELP OF VOLTAGE LEVELS - Google Patents

Description

C 2775

JPN / F / C / RCH

\\ _t Sep. 1973

COMPAGiTIE INDUSO? RIEIIE DES TELECOMMUNICATIONS CIT-AIßATEL 12, rue de la Baume, 75008 PARIS (France)

DEVICE FOR TRANSMISSION OF TELEPHONE NUMBERS WITH THE HELP OF

TENSION LEVELS

The invention relates to a device for transmission of telephone numbers with the help of DC voltage 3 levels,

In the field of telecommunications, numerous phone number fahlvorrichtungen are already known that with Work direct current. In particular, the applicant's French patent specification No. 1 * 525.030 describes a device known, in which the number printed on the keypad of a telephone set in the switching office measuring the line current twice in succession is identified, the measurements being made on two resistors characteristic of the relevant digit, the

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j / ί ■? .-

with the help of two working contacts that go through at the same time the corresponding numeric key is pressed, are connected in parallel on the line; the working contacts are selected by the intersection of a vertical and a horizontal rail of the keyboard, the one below this Button lies.

Such a device is prone to failure mainly because of the length of the lines to which the resistors belong, is different; consequently, the measurements are due to the added resistance of the lines falsifies this fact requires more or less extensive compensation facilities for this system,

The invention is intended to remedy this disadvantage and relates to a device for transmitting telephone numbers With the help of DC voltage levels that work extremely quickly and safely.

The invention also relates to a device whose receiver part has very small dimensions.

The device according to the invention for the transmission of telephone numbers with the aid of voltage levels is found especially in the field of personal life. It contains a keyboard on the sender side through which a Crossbar system is operated, which acts on the construction of circuits, in which the direction of current in each The scanning process is reversed, and on the receiver side a receiver corresponding to the transmitter, characterized in that

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that the circuits of the transmitter part contain conductor elements, which become effective in the circuit by pressing a key on the keyboard and which know the line voltage bring it to two successive different levels, the receiver being equipped with electronic means with which the two successive voltage levels can be read and according to a bitemary code can be encrypted in two cycles, as well as with storage devices with which the corresponding codes can be registered.

According to an advantageous embodiment of the invention, the device is characterized in that the Semiconductor elements are normal diodes and Zener diodes, which are connected in series in the line loop of the touch dial telephone are arranged and each take effect in the line if the one horizontal or vertical rail of the The contact assigned to the keyboard is operated

According to a further advantageous embodiment According to the invention, the device is characterized in that to it

- Crossed rods belong, three of which are vertical, V1, V2 and V3, their respective contacts a Zener diode Z1, a Zener diode Z2 or a diode D1 can be effective in the line loop lying in the same direction, and four horizontal rails H1, H2, H3 and H4, with the H2, H3 and · H4 assigned respectively Contacts a Zener diode Z3, a Zener diode Z4

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or, let a diode D2 become effective, the opposite directions to Z1, Z2 and D1 lie,

and keys numbered from 0 to 9 in a keyboard, of which keys 1 to 8 are on the rails (H1 V1), (H1 V2), (H1 V3), (H2 V1), (H2 V2), (H2 V3), (H3 V1) or (H3 V2) act, while H3 and V3 do not act together act and the button 0 (H4 V2) and button 9 actuate an additional contact through which an additional Zener diode Z5 and an additional diode D3 take effect.

According to another advantageous embodiment According to the invention, the device is characterized in that the Zener diodes or the normal diodes become active when paired in the line caused by the keys, connected to their cathodes in a common point so that since the supply voltage of the line is automatically reversed by the receiver, each diode and (or) zener diode, which is effective in the line, is flowed through one after the other in both directions by current and so one after the other two Can give voltage levels on the line.

According to a further advantageous exemplary embodiment the device is characterized in that all the contacts corresponding to the crossbars of the keypad are so are connected in series so that they close the loop without resistance as long as no key is pressed.

According to a further advantageous exemplary embodiment the device according to the invention is characterized in that the Zener diodes Z1 and Z3 as Zener diodes

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worth about a quarter of the supply voltage of the electrical Circuits supply while the Zener diodes Z2, Z4 and Z5 the Zener value is about two thirds of the supply voltage,

The device according to the invention preferably has dös one and / or other of the following characteristics ϊ

The means by which the successive voltage levels are read and encrypted are in divided into two groups of three, with the readers of each group sharing their inputs with one or the other of the two lead wires are connected and each read output is connected to a corresponding transmission gate, with each group of these gates one after the other every coded voltage level can be transmitted j

the storage means for registering the encoded Spanrmngsstuf en comprise two groups of three bistable Elements, each connected to a transmission gate are?

the input circuit of each reader one and the same Group has a reference Zener diode that is connected to the Diode or Zener diode, with which the loop is closed, connected in series and polarized in the same direction, where the Zener value of the reference diode of the rank of the reader depends and in relation to the value of the supply voltage for the first reader in each group is low, for the second reader in each group is medium (about half of the supply voltage) and strong for the third reader in each group

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(approximately equal to the supply voltage), so that the voltage drop of a reversed fed in the loop effective diode reduced supply voltage the voltage level of the line on the Ie se inputs emits, whereby at least one of the readers in each group becomes transparent (state 1) if the absolute value of the sum of the voltage drops of the effective diode in the loop and the reference diode smaller is than the supply voltage j

each output of the bistable elements of the first group is connected to a corresponding input of an OR-NOT gate connected in such a way that the supply voltage on the wires of the line after the register coded during the first reading process a first voltage level in the registers of the first group is reversed and that in the second read a second voltage level coded on the bistable elements of the second group can be registered j

each of the digits 0 to 9 on the keyboard corresponds to a bitemary code.

In the following, with reference to the accompanying drawings, an exemplary embodiment of the invention is shown Device described;

1 shows the device according to the invention equipped with circuits for transmitting the voltage levels represent.

Fig. 2 shows a diagram with the various

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Line voltage levels which are selected by the reader with, on the one hand, the Zener value of a reference diode present in the input circuit of each reader and, on the other hand, the Zener value of the diode effective in the loop.

3 shows the reading and transmission circuits in the receiver part of the device according to the invention.

The Pig. 4 and 5 represent one of the readers of the receiving part "or a group of these readers on the line for the selection and decoding of those given on the line Voltage levels.

Pig. 1 shows a basic circuit diagram of the keypad according to the invention. It comprises horizontal rails labeled H1, H2, H3 and H4 _J and vertical rails V1, V2 and V3 · Each key 1, 2, 3, 4, 5, 6, 7 , 8, 0 of the keypad actuates a horizontal and a vertical rail ^ with each of the horizontal rails H1 to H4 each having a corresponding contact p, q, r or s and each vertical rail V1 to V3 a corresponding contact 1, m or η opens. Only key 9 opens a single contact t. By opening certain contacts, a diode or a Zener diode becomes effective in the line loop a1-b1.

The following processes can be triggered by pressing buttons 1 to 9:

Key 1: opens contacts ρ and 1 and takes effect the single Zener diode Z1 with the value xj

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Key 2: open the contacts ρ and m and the single Zener diode Z2 with the value y becomes effective;

Key 3: Open contacts ρ and η and take effect the single diode D1;

Key 4: Open contacts q and 1 and take effect of the Zener diodes Z3 and Z1 with the value x, which are in opposite directions are switched;

Key 5: open the contacts q and m and the Zener diodes Z3 (value x) and Z2 (value y) _f, which are switched in opposite directions, come into effect;

Key 6: contacts q and n, Zener diode Z3 (x) and Diode D1, which are connected in opposite directions;

Key 7: Contacts r and 1, Zener diode Z4 (y) and Z1 (x), switched in opposite directions;

Key 8: contacts r and m, Zener diodes Z4 (y) and Z2 (y), switched in opposite directions

Key 9: contact t, Zener diode Z5 (y) and diode D3, switched in opposite directions;

Key 0: Contacts s and m, diode D2 and Zener diode Z2, switched in opposite directions.

The Zener diodes belonging to the circuitry of the keyboard have two different Zener values, as shown in the diagram of Fig. 2 are shown in the form of dashed lines. The Zener diodes Z1 and Z3 from FIG. 1 have the same

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Zener value χ represented by the section Zx in FIG and in this exemplary embodiment is low in relation to the supply voltage V (for example χ -> t 1/4 V); the Zener diodes Z2, Z4 and Z5 have the same mean Zener value y, which is determined by the section Zy (y ■; · => 2/3 V) is shown »

The subscriber set P is at the points al and b1 connected to the line in such a way that when the handset is lifted, the line wires pass through the telephone (subscriber contact CO) and About the height of all closed contacts on the keyboard form a loop.

If any key on the keyboard is pressed, the line current coming from the central office will be in two cycles on the semiconductor element (~ s) switched on in the loop by this key, whereby the Line is supplied with two successive voltage levels. For example, if key 1 is pressed (Contacts ρ and 1 open) j then flows under the assumption that in one first phase the supply voltage on wire a of the line (not shown here) is positive, the line current duroh the following circuit: point al, subscriber contact CO, break contacts η and m, Zener diode Z1, which is fed in reverse becomes, normally closed contacts q, r, s and t, point b1

The current lowers the voltage level in the line to the Zener value χ of the Zener diode Z1.

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The line is thus (Fig. 2) brought to a high level (Nh), which has a maximum value (Nha), normal value (Nhn) or minimum value (Nhi), depending on whether the supply voltage is maximal (Va), normal (Vn) or minimal (Vi).

In a second phase, in which the central office reverses the supply voltage on the line wires, the diode Z1 is fed directly and the level reached is practically the same as that of the galvanically coupled loop when all keys on the keyboard are in the rest position.

Analog appears z _# B "by pressing the button 5 in a first stage, a middle stage Nm on the line in which the reverse-fed Zener diode Z2 (Zener value of y) is effective, and in a second phase a high level Nh by making the reverse fed Zener diode Z3 (Zener value x) effective «

When certain keys are pressed, a third level appears on the line. For example, through Pressing the button 6 in a first phase the diode D1 will be switched on in the loop. This diode blocks the Current flow when fed in reverse so that the voltage between points al and b1 is practically the same the supply voltage is (section Db in partly dashed, partly solid line in Fig. 2), and the line takes then the low level Nb. In a second phase, the Zener diode Z3 gives its after reversing the current Zener voltage χ on the line and determines a high

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Level, with the voltage drop across the diode D1, which is now is fed directly, can be neglected.

FIG. 3 shows that part of the device with which the voltage levels transmitted by pressing the keys on the keypad can be received and decoded according to FIG. 1. The lead wires (not shown here). a and b lead to points al and a2 on the one hand and b1 and b2 on the other hand (al and b1 are drawn in FIG. 1) and thus connect the keypad of the subscriber set to the receiver of the exchange, who via the connection points h, j and k, pr, am to fm and am to Tm is connected to a recording device (not shown in the drawings). The point b2 is connected to the read inputs A, B, C connected in parallel. The output of each of these readers is connected to an input of the corresponding gates AA, BA, CA and to a corresponding input of the three-input gate P1. The output of P1 is connected to the connection point j and to a first input of a gate P2, the second input of which is connected to the point k and to the gate PM. The output of P2 is connected to an input of the gate PM. The gates PM and pH are fed back crosswise and form a bistable trigger circuit. The same applies to the gates labeled AM AS to FM - FU. The gates AA, BA and CA are connected to a second input together with the output of the gate PM, while the outputs of these gates

A09813 / 0890

are connected to the corresponding inputs of the gates ÄÜ, BÜ, ÜÜff? The output of PM is connected to point pr. The output of PM is connected to the coupled inputs of the gates CM-DM, BM-EM and AM-FM via a common point. The output of the gates AM to Fl are connected to the connection points am to Tm and to the corresponding inputs of an OR-NOT gate RP.

The end of the first reading process is determined by an element F1L to which an OR gate CI belongs, which is assigned to a fixed delay line RC1. The outputs of gates AM, BM, and CM are respectively _mrt: connected to the corresponding inputs of the gate CI. The output of the fixed delay line RC1 is connected to the input of a reversing feeder AD, with which the supply voltage can be switched. This inverting feeder is equipped with an inverting amplifier 11, which is assigned to a delay line RC2 and an inverting amplifier 12. The output of RC2 is connected to the input of 11 via a common terminal and to a resistor R1, the other end of which is connected to point b2. The output of 12 is connected to a resistor R2, the other end of which leads to the point a2. Readers D, E, F are connected with their inputs in parallel to the point a2 and with their outputs to an input of the gates DA, EA or FA, while their second input leads to a common connection point h. The outputs of the gates AA,

Λ09813 / 0890 ^ *

, ··· FA are connected to the corresponding inputs of the gates, SB ₁ ,., Hi. All AND gates used are designed as reverse gates (UITD-IiICHT),

When explaining the operation of the receiver part, the earth is indicated by state 1 and the supply voltage battery characterized by the state O.

The availability of the circuits is checked and guaranteed according to the following procedure: as long as the receiver of the telephone subscriber set P is on the cradle, the contacts of the subscriber contact GO are open (Pig, 1) and the line loop is not established. State Q is present at the outputs of readers A, B _{f 0.} Gate P1 supplies a blocking state 1 on terminal j of the recorder, which waits for the loop and supplies state 1 at terminal k. For simplification, the states 0 or 1 actually present on the outputs of the gates should only be identified by naming the associated gate will. The gate P2 is in the state 0, as is the gate PM of the flip-flop PM-PM. The gate PM "blocks in state 1 the gates AM to I ¹ M in state 0, the gates AA, BA and CA have the state 1. The gate CI, whose three inputs show 0, is in the state 1. Therefore is State 0 (battery at point b2) and state 1 (earth at point a2) in reverser 11. Readers D, E and F are in state 1. Since the points on

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Ms fm have the state 1, the gate RP is at O.

The loop is established as follows: when the caller goes off-hook, points a2 and b2 des Receiver connected to one another via the normally open contact of the subscriber contact and the normally closed contacts on the keyboard (Pig * 1). The state 1 delivered by the reverser 12 is applied to the point a2, then forwarded to point b2 through the keyboard loop, and readers A, B and C become transparent and each deliver a state 1 at their outputs. The gate P1 changes to the state 0 and thus informs the registrar (Point J) to close the loop with. The registrar confirms this information by replacing state 1 with state 0 in point 1. The gate P2 with its two inputs set to 0 adopts state 1 and thus changes the state of the bistable multivibrator PM - PM, which determines that the recipient has picked up. This becomes the registrar by opening the gate PM notified that state 1 passes to point pr. When this signal is received, the registrar sends the dial tone on the caller's line. Since the gate PM has changed from state 1 to state 0, it now clears the blocking state 1 on the input of the gates AM to PM, which retain the state 0. The recipient is now ready to be coded by pressing the keyboard

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Receive phone numbers.

The reception of the telephone number code corresponds to the following How it works: "During the first reading process, the caller presses a number key and, depending on the number, gives a high, medium or low voltage level on the line so that one or two readers A, B, C are blocked (state 0 on the output). The gate P1 assumes the state 1 again and the gate P2 to the state 0.

The corresponding gates AA, BA and CA will then be enabled (state 1 on the output) and 'change the state of the associated bistable flip-flops that register the first part of the code combination in the memory registers AM to CM, with the flip-flops indicating the state 1 of the corresponding gate take over.

At the end of this first reading of the line by readers A, B and C, at least one of the inputs takes on of the gate CI of the part P1L the state 1, whereupon the The gate at the output supplies the state 0 and the reversing feeder AD reverses the supply voltage in the lead wires. The inverter 11 and the point b2 are in state 1, the inverter 12 and the point a2 in state 0 ,.

The fixed delay lines RC1 and RC2 are provided the reverse command for the supply voltage with a delay cycle, so that the correct position of the elements of the first part of the receiver is secured before the second read.

During the second reading, at point b2 with the

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Point a2 is connected via a loop, the diode or Zener diode, which was switched into the line during the first reading process but was not effective, now supplies a new voltage level when the voltage is reversed on the line. This is decoded by the readers D, E, F, of which one, two or three, depending on the case at hand, are blocked (state 0). The gates DA, EA and FA corresponding to the blocked readers are released (state 1) and change the state of the associated flip-flops DM -Wi to FM-PM, which register the second part of the code combination in the memory registers DM to FM.

The digit thus transmitted in coding to the bistable multivibrator circuits is stored in the recorder with the help of the identification stored at the points on to fm.

After the delay cycle of the fixed delay circuits RG1 and RC2, the supply voltage appears as initially with state 1 at point a2 and the reading position in b2, this reading process confirming the first, previous reading process as long as the corresponding numeric key is pressed has not been released.

At the end of the transmission process for a digit, the diodes are taken out of the loop again if the Button is released. Readers A, B, C and D, E, F all become transparent (state 1) while the trigger circuits AM-IM to FM-H maintain their position,

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that they had when registering the coded digit. The change of state in the gate Pl gives the information at point j, that the digit transmission has ended.

If you hang up while dialing the number, the following procedure results: the listener is before the end of the Number dialing process is hung up, the subscriber contact opens the line loop and readers A, B, C are blocked (state 0). The gates AA, BA, CA, their two Inputs have the state 0, assume the state 1. The gates IM to ^ M then take over the flip-flops the state 0 and the gates AM to CM of these flip-flops have the state 1. Since all inputs of the gate CI are at 1, it delivers the state 0. The inverter II is located in state 1 and 12 in state 0.

Readers D, E, F are in state 0 and gates DA, EA and FA are in state 1, so that gates Wi to FM of the flip-flops are in state 0 and gates DM to FM of these flip-flops are in state 1. The gate RP, the inputs of which are all 0, assumes the state 1 and causes the change of state of the flip-flop PTf-PM: the gate PK assumes the state whereby all register circuits are reset to their initial state in which they are available (IM to M in state 1). The gate RP again assumes the state 0 and enables the flip-flop circuit PM-PM.

In Fig. 4 a basic circuit of a reader 40981 3/0890 '^'

shown as it appears under A to F in Fig. 3; a reference Zeher diode Zr was added to its input circuit, one of the features of the device according to the invention is.

The anode of the Zener diode is connected to the input of each reader, the cathode to an input resistor RE of the reader tied together. The reader itself consists of two transistorized stages: the first includes the NPN transistor Tl, the two resistors RBl and RCl and the diode DEl is assigned; the second, which is connected to the first via resistor R2 is connected, consists of the PNP transistor, which the Resistors RB2 and RC2 and the diode DE2 is assigned. The reader is designed as an amplifier.

If there is a line voltage at input E of the reader before, which is greater than the absolute value of the threshold voltage of the reference Zener diode, the transistors Tl (NPN) and T2 (PNP) of the reader are released, which then has a positive supply voltage at its output S (state 1) delivers.

The line voltage is lower than the threshold voltage, the transistors T1 and T2 can not be released, and the output of the reader has a negative polarity (state 0).

Fig. 5 shows the readers A, B, C when the line voltage is present during the first reading process. At the organ PS

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it is a well-known protective device that is connected to the reader inputs via a common terminal and is intended to protect against possible overvoltages in the line. If a key (digit C * -) is pressed, the corresponding normally closed contact on the vertical rail opens and, for example, puts a Zener diode Zi into the line, which is fed in reverse {+ at point a2 when the inverter 12 has state 1 having). The introduced into the conduit diode Zi is aligned in the same direction as the reference diodes ZrA, ZrB and ZrC is the corresponding readers A, B, C. Each of these diodes anschliessand, which has been described above with reference to FIG. K with the corresponding read circuit , tied together. ·

The operation of the circuit shown in FIG is as follows: the values of the reference diodes are proportional to the sections shown in the diagram of FIG are shown in solid lines. For example, if the diode Zi put in the loop has a Zener value χ (sections Zx in dashed lines), it must be determined that the sum of the Zener voltage drops va + vx, which is less than the supply voltage Vn, is the basis of the Polarized transistor TlA, namely to a negative voltage, which is lower than that of the emitter, which is almost so is as large as the supply voltage Vn. This supply voltage Vn (normal voltage) can be between the stages Va (maximum voltage) and Vi (minimum voltage) vary. The transistor TlA is

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permeable and reader A assumes state 1 (positive polarity at output S).

The same applies to reader B, who also assumes state 1, because:

² | vb | + ivxl <V

In contrast to this, the reader C assumes the state (transistor TlC blocked), because:

Jvcj + jvxl> V

This is how the keyed-in digit determines the first

Reading process a high voltage level (Nh) in the line,

this voltage level causes the following states in the readers:

A = I

C = O
and the corresponding state in the flip-flop registers:

IM «1 AM = 0

Wl = I BM = 0

WHERE CM = 1

During the second reading process, for example, a Zener diode Zy is activated due to the voltage reversal (normally closed contact the horizontal rail corresponding to the key).

Following the same procedure, the following states are obtained for readers D, E, F:

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| vd | + tvyj <CV, so D = I fvef + jvyj> V, so E = O jvfj + jvy {> Y ₁ so F = O

and for the corresponding registers:

= I DM = 0

IB = O EM = 1

= O FM = 1

The number is therefore registered according to the following code:

AM = 0 DM = 0

M = O EM = 1

CM * = 1 FM = 1

Since the Zener diodes Zl and Z3 of the keyboard (Fig. 1) in this exemplary embodiment have the same weak Zener value χ and the Zener diodes Z2, Z4 and Z5 have the same mean Zener value y, is the number that corresponds to the first The value χ that takes effect during the second reading process and the value y that takes effect during the second read process corresponds to the number (Zl = χ volts and Z4 = y volts take effect).

The digit dL = η is thus represented by the code 001 011, which corresponds to a double representation of the ternary code, which is why the coded representation of the digits 0 to 9 sent by the keyboard is called biternary.

The biternary code of the digits 0 to 9, the one 409813/0890 " ^{/ #}

that represents characteristic features of the invention is set out in the following table in which the state of the Register AM to FM of the latch circuits is specified for each digit transmitted.

1. Reading process AT THE BM CM 2. DM Reading process FM 1 0 0 1 0 M. 0 2 0 1 1 0 0 0 3 1 1 . 1 0 0 0 4th 0 0 1 0 O 1 5 O 1 1 O 0 1 6th 1 1 1 0 O 1 7th 0 0 1 0 0 1 8th 0 1 1 0 1 1 9 1 1 0 1 1 0 0 1 1 1 1 1 1

With certain buttons, a Zener diode and a normal diode can be switched into the line in opposite directions will. This applies to the key of the number 9, which by opening the contact t, the Zener diode Z5 with the value y and brings the diode D3 into the loop. From FIGS. 1 to 5 and the diagram in FIG. 2 it can be seen that the number 9 corresponds exactly to code 111 011 in the table above.

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When the button 9 (Fig. 1) is pressed, the contact t is opened and the Zener diode Z5 with the value y and the diode D3 switched into the loop. During the first reading process, the directly fed Zener diode Z5 has a very low one Impedance while the reverse fed diode D3 is blocked. The line is no longer fed (deep Step Nb), the supply voltage falls by its entire value, as is shown with the aid of section Db in FIG. Since the voltage at point B1 is zero (FIG. 5), readers A, B and C are blocked (state 0 on the output). the Transmission gates AA, BA and CA (Fig. 3} take the state 1 and the registers AM, IM, "GM have the status 0, the registers AM, BM and CM supply the state 1 of these gates. .

During the second reading process, the Zener diode Z5 is fed in reverse and causes one in the line Voltage drop y, whereby the readers of the second reading process are set as follows:

■ This position is the same as the one before when examining the number 7 during the second reading was established ^ and it results:

DM = 0

EM = 1

FM = 1 ./.

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So the number 9 is represented by:

AM = 1 DM = 0

BM = 1 and EM - 1 CM = 1 FM = 1

The industrial scope of the invention relates to a transmission device of voltage levels, the receiver side with the help of printed circuits is built and which is suitable in all respects for use in the field of telephony. In particular, can the receiver part can be constructed with integrated circuits, which are then printed on printed circuit cards be attached.

Various changes can be made within the scope of the invention; in particular, the used Keyboard can be chosen arbitrarily, in which case the diodes and Zener diode circuits would be constructed accordingly. ■ Furthermore, the transistors with which the readers are equipped can be rotated in reverse order if the polarity of the supply voltage of the line is reversed; the same applies to the Zener diodes of these readers and to the Zener diodes of the keyboard circuits.

- Claims 409813/0890

Claims (12)

PATENT CLAIMS qV) Device for the transmission of telephone numbers with the help of voltage levels, especially in the field of Telecommunications with a keyboard on the receiver side, through which a crossbar system is operated, which is on affects the construction of circuits in which the current direction is reversed with each keying operation, and on the Receiver side a receiver corresponding to the transmitter, characterized in that the Circuits of the transmitter part contain semiconductor elements, of which by pressing a key on the keyboard in the Circuit at least one can be effective and the line voltage on two successive different ones Bring stages, the receiver being equipped with electronic means with which the two successive Voltage levels can be read and encrypted in two cycles according to a biternary code as well as storage devices with which the corresponding codes can be registered. 2. Device according to claim 1, characterized It is noted that the semiconductor elements are made up of normal diodes and Zener diodes, the in the line loop of the telephone set with keypad are connected in series, each diode being connected to a horizontal and a vertical rail of the 40981 3/0890 ./. Keypad when actuating the contact into the loop is taken. 3. Device according to claim 2, characterized in that their crossbars three vertical rails (Vl, V2 and V3), through their corresponding contacts a first Zener diode (Zl), one second Zener diode (Z2) or a first normal diode (Dl), which are aligned in the same direction in the loop, are switched on, furthermore four horizontal rails (Hl, H2, H3 and H4), with the contacts of the last three rails (H2, H3 and H4) a third Zener diode (Z3), a fourth Zener diode (Z4) and a second normal diode (D2), which are opposite to the first diodes (Zl, Z2 and Dl), turn on, as well as include a keyboard of 10 keys numbered from 0 to 9, where the keys 1 to 8 (Hl Vl), Press (Hl V2), (Hl V3), (H2 Vl), (H2 V2), (H2 V3), (H3 Vl) or (H3 V2) while key 0 is on (H4 V2) and the Button 9 acts on an additional contact, through which an additional Zener diode (Z5) and an additional simple Diode (D3) can be put into the loop. 4. Apparatus according to claim 3, characterized in that the Zener diodes or the normal diodes when switched on in pairs in the line using the buttons with their cathodes on a common Clamp so that since the supply voltage of the line is automatically reversed by the receiver, each diode 409813/0890 ^ or Zener diode connected in the line, one after the other current flows through it in both directions, creating two successive voltage levels on the line admit. 5. The device according to claim 4, d ad u r c h gekennze ichnet that all the keyboard rails corresponding contacts are connected in series so that they close the line loop without resistance when no key is pressed. 6. The device according to claim 5, characterized in that the first and third Zener diode (Zl and Z3) have about a quarter of the supply voltage of the electrical circuits as Zener value and the Zener value of the second, fourth and fifth Zener diodes (Z2, Z4 and Z5) is about a third of the supply voltage amounts to. 7. Device according to one of the preceding claims, characterized in that the means for reading and coding the successive voltage levels are divided into two groups of three, taking the readers of each group with their inputs a common terminal of one or the other of the two lead wires and each read output with a corresponding one Transmission gate is connected and each group of gates sequentially each coded voltage level can transfer. A09813 / 0890 8. The device according to claim 7, characterized in that the storage means for Registering the coded voltage levels comprise two groups of three bistable elements, each connected to one of the Transmission gates are connected. 9 .. Device according to claim 8, characterized in that the input of each reader of the same group contains a reference Zener diode which is connected in series and aligned in the same direction with the diode or Zener diode which is effective in the line , whereby the Zener value of the reference diode depends on the position of the reader and in relation to the supply voltage for the first reader in each group is low, close to zero, for the second reader in each group it is medium, about half the supply voltage »and for thick third reader each group approximately equal to the supply voltage, so that the effective by the voltage drop of a · inversely fed Dioäe veirzu.iid.eYte supply voltage, the voltage level of the line at the inputs of the reader is, wherein at least one of the readers of each group becomes permeable when the absolute sum of the voltage drops of the diode acting in the loop and the reference diode is less than the supply voltage. 10. The device according to claim 9, characterized in that each output of the bistable Elements of the first group with a corresponding ./. Λ 0 9 8 1 3/0890 Input of an OR-NOT gate, so that in the lead wires after a first read operation of a first voltage level on the registers of the first Group coded registration that causes the inversion of the supply voltage and so that of a second Reading process of a second voltage level on the bistable Coded registration for elements of the second group is possible. 11. Device according to one of the preceding claims, characterized in that each of the digits 0 to 9 on the keyboard corresponds to a biternary code. 12. The device according to claim 11, characterized in that the biternary code each Digit looks like this, with the first part of the code a first reading, the second part a second Reading corresponds to: 1. Reading process 2. Reading process Section 1 0 0 1 0 0 0 "2 0 11 0 0 0 ¹¹ 3 111 0 0 0 « On 0 0 1 0 0 1 η 5 0 11 0 0 1 »6 111 0 0 1 « ₇ 0 0 1 Oil η 8 0 11 Oil η 9 111 Oil "0 0 11 111 0 9 8 1 3/0890