DE1209613B - Circuit arrangement with a ring counter for electronic telephone exchanges - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

H04m

German class: 21 a3 - 32/01

Number: 1209 613

File number: P 27191 VIII a / 21 a3

Filing date: May 23, 1961

Opening day: January 27, 1966

The invention relates to a circuit arrangement for electronic telephone exchanges with multi-digit subscriber numbers, with a ring counter, which consists of several cold cathode gas discharge tubes and which has so many outputs has how the number of different digits is represented by the counter as the first digit of the Subscriber number are to be processed, and each of which outputs these to a different one Level of a further counter can be switched that processes one of the digits that the next digit of the subscriber number form, and with a control tube that turns off the tubes controls in the ring counter.

In such circuit arrangements, the discharge tubes of the ring counter are operated in such a way that a first pulse applied to a line on which pulses are given according to a dialed number changes the potential at the ignition electrode of a first tube so that it ignites. A second tube is prepared or pretensioned using conventional time constant circles so that it ignites as soon as a second pulse arrives on the pulse line. The potential at the cathode of the second tube increases so that the same potential is applied to both cathodes. To erase the first tube, as is well known, the next step is that a capacitor located between the cathodes can be discharged through the previously described state of the cathodes, the discharge current, which also flows through the cathode resistance of the first tube, here becomes the anode current of this Tube added so that the anode-cathode potential falls below the value of the burning voltage and the tube goes out. The second tube remains ignited and prepares a third, which is ignited by the third pulse in the same way as already explained. The second tube is extinguished again and the first tube cannot ignite again because its effective anode voltage is too small due to the voltage drop across its cathode resistance. In this way, z. B. a decade for counting ten pulses can be built up with ten such tubes, or any number of pulses can be counted by connecting several decades in succession, in which case a control tube can be provided that detects the extinction of the counter tubes in the ring counter Controls discharging of a decade and prevents the first tube of the first decade from being re-ignited when receiving the pulses for the second decade or the second call number position. The invention is circuit arrangement with a ring counter for
electronic telephone exchanges

Applicant:

Pye Limited, Cambridge (Great Britain)

Representative:

Dr. H. Wilcken, patent attorney,

Lübeck, Breite Str. 52-54

Named as inventor:

Donald Brian Delanoy, Cambridge

(Great Britain)

Claimed priority:

Great Britain May 25, 1960 (18 471)

essentially the object is based on the possibility that occurs in such circuit arrangements turn off that uncontrolled or unintentional pulses, especially single pulses, which Do not follow any more of the dialing pulse sequence, cause faults in a telephone exchange and can build up unnecessary faulty connections.

This object is achieved according to an essential feature of the invention in that in the initially mentioned circuit arrangement of the ring counter has a self-extinguishing tube, which in a time constant circuit after a delay time determined by the time constant is to a tube of the counter, which ignited after receiving a single pulse at the counter input has been deleted when this single pulse does not contain any further pulses of a dialing pulse train follow before the specified delay time has expired.

The version to be described is intended to be the first counter in a telephone exchange twenty connections are used, in a type of exchange in which each subscriber a call number is assigned that consists of two digits, with the digit 1 never being the first Digit is used. This means that the twenty subscribers will have twenty phone numbers for the two decades given to twenty nine and thirty to thirty nine.

509 780 / SI

The first counter, which is provided for each connection path of the switching system, therefore responds to the dialing pulses that reproduce the first digit of a subscriber number to be called, and determines which stage of the second counter should respond to dialing pulses that the second Represent the number of the called subscriber number.

The circuit consists of six cold cathode gas discharge tubes, of which Vl is a self- extinguishing tube and V 2 to V 5 form an interrupted ring counter and V 6 form a control tube. Dialing pulses are fed to the ignition electrodes from F 2 to VS via terminal 1. The ignition electrode of the tube V 2 is biased via the terminal 2 from another part of the connecting device by a circuit of Rl, R2, Cl and MR 1, which has a fast discharge with a slow charging time constant. This connection ensures that the biasing potential is removed from F2 as soon as the connection devices are released, in order to prevent F 2 from bumping as a result of the transitions to the release.

In the embodiment described, the first digit of a subscriber number is either 2 or 3, and therefore two outputs are provided to the second counter, one of which is labeled "Level 2" and the other as "Level 3". The cathode of the tube F 3 is connected to the second counting stage 2 through the terminals 3, 4 and 5 and the cathode of the tube VA is connected to the second counting stage 3 through the terminals 6, 7 and 8. Each stage of the second counter can consist of a number of tubes, the number of which is equal to the number of digits to be handled by the second counter, each tube having an output which is connected to a different subscriber number. The tubes can consist of cold cathode gas discharge tubes which are arranged in a ring counter. In the present embodiment ten tubes are provided for each stage of the second counter in order to produce outputs which respond to the second digits 0 to 9 of a subscriber number. It will be understood that if there are more than twenty subscribers, it will be necessary to provide a larger number of stages for the second counter, one for each additional first digit used for a subscriber number, and additional ones as well Tubes, one for each additional digit, to be provided in the ring counter of the first counter between VA and F 5.

The operation of the circuit will now be considered after selecting either the number 1, 2, 3 or a number greater than 3 for the first digit.

Choosing the 1st

After the dial pulse is supplied to the ignition electrode by F2 from terminal 1, this tube ignites and charges the time constant circuit R3-C2 , which ignites the tube V1 after charging. This tube is arranged in a self-extinguishing circuit and generates a pulse at its cathode which is applied to extinguish the tube F 2. The circle is released within 0.2 seconds. No output is generated from the first counter. So this is the effect of the circuit in the event of false pulses.

Choosing the 2nd

The first dial pulse ignites the tube F 2 in the manner described above, and the second dial pulse extinguishes F 2 and ignites F 3. The second dial pulse comes 100 milliseconds after the first dial pulse on, d. H. before the time constant circuit i? 3-C2 is charged enough to ignite Fl. F 3 remains ignited, and the output is taken from its cathode ίο via terminal 3 to the first tube bias in the second counter stage 2.

Choosing the 3rd

The first two dial pulses fire F 2 and V 3, as described above, and the third dial pulse triggers VA. The time constant circuit RA-C 3 in the cathode circuit of F 3 is used to prevent the first tube of the second counter stage 2 from igniting as soon as the dialing pulses pass through F 3. As soon as VA ignites, an output is taken from its cathode via terminal 6 in order to bias the first tube in the second counter stage 3.

Choosing a number greater than 3

If the number 4 or a higher number is dialed, the first three dial pulses operate the circuit in the manner described above, and the fourth dial pulse ignites the tube F 5. The time constant circuit R5-CA in the cathode circuit of the tube VA prevents the first tube of the second Counter level 3 on ignition as soon as the pulses pass through. F5 in turn ignites V6 via MR2, which means that tube V 5 goes out. The cathode capacitors of tubes F3 and VA are connected to the cathodes of the first tube of the associated stage of the second meter via terminals 4 and 7 instead of to the ground terminal of the first meter. This is done to prevent the tubes of the second meter from re-igniting after they have gone out due to the charge on the capacitors.

The following dialing pulses represent the second digit of a called subscriber number and activate the selected level of the second counter. The first pulse also ignites the tube F 4 or F 5 depending on the selected level of the second counter and the tube V 6 is also ignited as soon as the first tube of the selected level of the second counter has ignited, either via R 6 to left ignition electrode from V 6 for stage 2 or through the diode MR 3 and Rl to the right ignition electrode for stage 3. As soon as the tube V 6 is ignited, the common cathode line via Mi? A DC voltage is supplied to 5 in order to keep the cathodes of the tubes F 2 to VS sufficiently positive and to prevent re-ignition of F2 when the following pulses of the pulse train, which represent the second digit, are received. V6 is cleared by a pulse received at terminal 9 from another part of the connector.

The tube V6 also works in conjunction with a diode MR3 which is connected to its anode in order to control the supply of the busy signal to a calling subscriber via the terminal 10 when the subscriber whom he has chosen is already busy. If a busy subscriber is dialed, V6 does not extinguish, and the diode MR A is therefore de-energized as a result of the anode voltage drop from V 6.

switched when it conducts, thereby allowing the busy signal to be supplied to the calling party through another part of the circuit, not shown. As soon as V 6 is cleared and the diode MR 4 therefore conducts, it feeds a positive voltage across the terminal 10 in order to switch off the busy signal from the subscriber.

Terminal 11 receives a release pulse which, via terminals 5 and 8, steps 2 and 3 of the second counter is supplied.

In a modification of the first counting circuit, the biasing of V 2 is no longer effected via terminal 2. Instead, V 2 can be biased by a simple voltage divider from the high-voltage line or alternatively from the anode of the V 6 tube. An additional tube can also be included in the circuit to ensure smoother operation as soon as one participant tries to call another Calling a subscriber who is already busy. The extra tube is fired by V 6, which itself is fired by the first dial pulse of the second digit through a delay circuit the delay of which is no longer than the time required to dial any number in the second counter. The additional tube is self-extinguishing and provides a release pulse to the second meters to ensure that they are free at the end of the call that has already taken place. A rectifier is necessary to avoid that this pulse extending from the additional loan tube by the counter and back to the release of V. 6

Claims (5)

Patent claims: 1. Circuit arrangement for electronic telephone exchanges with multi-digit subscriber numbers, with a ring counter consisting of several cold cathode gas discharge tubes and which has as many exits as the number of different digits that go through the counter as the first digit of the subscriber number are to be processed, and each of them these outputs can be switched to a different level of another counter, who processes one of the digits that form the next digit of the subscriber number, and with a control tube which controls the extinction of the tubes in the ring counter, characterized in that, that the ring counter has a self-extinguishing tube (Fl), which in a time constant circle after a through the time constant certain delay time takes effect to a tube of the counter, which after Receipt of a single pulse at the counter input has been ignited, then to be deleted, if this single pulse is not followed by any further pulses in a dialing pulse sequence before the specific one Delay time has expired. 2. A circuit according to claim 1, characterized in that the control tube (V 6) also controls the supply of the busy signal to a calling subscriber when the connection he has chosen is busy. 3. Circuit according to one of claims 1 and 2, characterized in that the dial pulses the ignition electrodes of the cold cathode gas discharge tubes, which form the ring counter, are fed. 4. Circuit according to one of claims 1 to 3, characterized in that the ring counter has its own tube for each stage of the next counting circuit, which is marked by a special Digit is shown. 5. A circuit according to claim 4, characterized in that each stage of the next counting circuit consists of as many tubes as the number of digits to be processed by this stage is, and that each of these tubes has an output to a further counting circuit connected or assigned to a subscriber number. Considered publications: U.S. Patent No. 1530,968; Bell Syst. Techn. J., 31 (1952), 5 (September),
Pp. 855, 856; "Circuit book for industrial electronics", 1955, pp. 76 to 78; Rumpf, "Electronics in telephone exchange technology", Berlin, 1956, pp. 129 to 133; "Components of Electronics", Berlin, 1959, pp. 187 bis 190, 195 to 198. 1 sheet of drawings 509 780/81 1.66 © Bundesdruckerei Berlin