DE1025023B - Selective call system for dialing telephone subscribers in voice radio networks - Google Patents

Description

GERMAN

Selective call sy stars in radio networks, especially In networks of the mobile radio service serve to select from a number of mobile radio stations, which located within the range of the fixed radio station, call a desired radio station and the rest To block radio stations. Systems are currently used for this purpose in which the vehicle call numbers are characterized by selectively evaluated double tones. The double tones are specific frequency series taken. Two systems are known:

1. the pure frequency code procedure with double tones from the frequency series (2 ⁰ ) for 45 subscribers (port radio system),

2. the decadal, time-staggered double tone method with double tones of the frequency series (jj) (Landstraßenf system).

In the port radio system, a double tone is sent out by the radio station for selective calls the called vehicle radio station must be acknowledged by calling back before it is switched off. Through this a high operational reliability of the selective call is guaranteed. Shadowing of the received energy has no effect.

The highway radio system, on the other hand, works with a sequence of messages sent in quick succession Double-tone impulses of about 200 ms duration. There is no criterion to control that allows whether the individual impulses have been correctly received and evaluated. That is why the Danger that individual impulses will be lost in the event of a drop in field strength and the choice made by the operator must be repeated. On the other hand, however, the highway radio system has connection options for a high number of participants and the decisive advantage of the decadal structure a dial-up connection. Exactly as in telephone dial-up traffic within the territory of the Federal Republic The connections in the selective call are also set up in a decadic, forward-moving manner manufactured. For this reason, the country road radio selective call method is used for cooperation suitable with the public telephone network.

Another advantage of the time-graded system, in which every digit of a decade is identified by a double tone is assigned, is that in a relatively simple manner the choice of participants the vehicle radio station can be made possible.

So far, in the territory of the Federal Republic of Germany, the selection of participants from mobile radio stations is still possible not introduced. The attempts made so far, by immediately sending out the election impulses Controlling the dialing devices of the public telephone network over the radio path has failed. Field strength drops, shadowing, etc.

S elective call system

for the choice of telephone subscribers in radio networks

Applicant:

German Federal Post Office,

represented by the President

the Central Telecommunications Office,

Darmstadt, Rheinstr. 110

Karl-Heinz Schmall, Karlsruhe,
has been named as the inventor

caused the wrong choice by losing individual impulses.

One has the problem of the direct dialing from the vehicle subscriber to the fixed subscriber with one Trying to solve the pulse system by sending out the identifying numbers for the individual call numbers carried out pulse series of different lengths centrally at the stationary station. The moving ones In this known system, stations have in addition to the emission of the first display pulse only to perform a counting function that, when the desired number of pulses is reached, a Triggers a return pulse, which stops the pulse transmission at the stationary station. With this system that is, a whole series of impulses are always sent out by the stationary station, which naturally arrive mutilated can.

The invention achieves absolute security against incorrect selection by someone who differs from the known Solution.

The invention relates to a system for direct dialing of any wired telephone connections from mobile radiotelephony systems, in which the mobile subscriber as a result Call and dial signals sent by tone combinations are received by a fixed radio station, acknowledged, after saving in normal dialing pulses

709 907/294

implemented and transferred to the telephone network.

The main feature of the invention is that each tone combination by the vehicle station is broadcast until an outgoing tone call consisting of similar tone combinations the stationary station the call facility of the vehicle station automatically to the next combination which advances the sequence forming the call number.

It is already known per se, a selective call signal to be answered by a callback to the radio station that sent the selective call Trigger signal. The callback is an additional sign that the remote station is ready for operation should display. As with the invention, it does not provide the criterion for switching to the represents the next element of the license plate to be broadcast by the mobile station.

In the method according to the invention, the double tones for a decade can be taken from a row (I). A call number dialed at the vehicle radio station is stored there using known methods, transmitted to the fixed radio station as a double-tone sequence, stored again and passed on to the telephone exchange with the correct frequency. The fixed radio station can automatically acknowledge the double tones in chronological order. It is possible to save phone numbers up to eleven digits.

According to a further development of the invention, the vehicle radio station automatically activates each call the own number is transmitted and acknowledged as a double-tone sequence. The arrangement works with the selective call facility together. The call charges can be easily changed in each case Record fixed station and together with the details of the day, the time, the phone numbers print of the calling party and the called party on the charge slip.

The described dialing system includes operational processing, device operation and billing largely adapted to normal telephone service. Statistical determinations are based on the fee slips can be carried out in a simple manner.

It is possible to also use the operational safety of the rural road radio selective call system in conjunction to increase with the proposed voting system by making selective calls from the vehicle radio station Sending your own call number double-tone sequence must be acknowledged.

It is advisable to add another audio frequency series of five for the direction of the vehicle to the fixed radio station Set tones, which compared to the usual selective call frequency series around a certain difference frequency is shifted. The requirements for the accuracy of these frequencies are moderate because of their Evaluation can be made in low-pass filters with a certain bandwidth.

For the direction telephone subscriber — radio subscriber the fixed stations can be assigned code numbers that were specified by the telephone subscriber the selective call number of the vehicle are to be dialed. The code number is decisive for calculating the fee.

The subject of the invention is based on the block diagram of the embodiment shown in the drawing explained in more detail according to the invention.

1. The dial and selective call devices of the vehicle radio station 1 contain:

a) Selective call from valer, consisting of the two mixer circuits 2, the low or band pass filters 3 and the associated circuits 4. The circuits can be transistor switching arrangements be executed. The tasks of the selective call evaluator are to advance the scanner 5 (Rotary selector) upon receipt of an associated selective call double tone and switching on and off of the transmitter 6.

b) Two LF oscillators 7 for the superposition frequencies of the evaluator. The oscillators can be equipped either with tubes or with transistors.

c) scanner 5, an eleven-part rotary selector. The scanner is used to switch the memory setting through to the LF oscillators one after the other.

d) Storage device 8. The task of this member is to assign the vehicle's own selective number mark and save the phone number selected in the vehicle.

e) audio frequency circuits 9 for switching on as frequency-determining Links to the low-frequency oscillators.

2. The fixed station 10 / transfer station 11 includes the following dial-up and selective call devices:

a) Memory and pulse transmitter 12 for storing the number transmitted by the vehicle and correct frequency forwarding to the telephone dialing equipment.

b) audio frequency converter 13, which has the task of receiving the incoming double-tone pulses at the fixed radio station to feed a certain amount of frequency shifted to the transmitter.

c) Charge printer 14. This device contains a mechanical printing mechanism for registering the Phone numbers and call charges.

d) Charge counter 15, which converts the counting pulses for charge printers.

The mode of operation of the selective call system according to the invention is explained in detail below:

1. Radio subscriber is called (selective call). After removal of the dial tone (2800 Hz) and sending of the first double-tone pulse is at the vehicle radio station on rotation step 1 of the scanner to the Difference frequency shifted double tone generated, which is superimposed on the selective call double tone in the evaluator and actuates the rotary magnet. The scanner is switched to the second rotary step and effected the generation of a new double tone, which is generated by superimposing the corresponding selective call double tone upon receipt UsAv leads to actuation of the rotary magnet again. to the last digit of the selective call number. The vehicle radio station is then switched to ready-to-speak.

2. Radio subscriber calls. The control unit and the selection device are designed so that when Pick up the handset and, if the channel is free, the call generator is automatically switched on interrupts the dial tone at the fixed station. Rotation step 1 of the scanner then becomes automatic the first double tone is emitted from the LF oscillators of the A counting device and sent to the fixed radio station receive. There it is converted into a double tone of the selective call frequency series and this sent again. At the same time, a billing printer is initiated that corresponds to this double tone To print the number on the fee sheet. The double tone is received by the vehicle radio station and is evaluated there as a double-tone selective call of the first digit of the own call number, so it can act as a rotary magnet of the pickup switch to the next double tone. In the same way, all Digits of your own phone number transmitted and from

the fixed station acknowledged. The scanner is only switched on when its own double tone has arrived correctly at the fixed station and the receipt has been received correctly.

At the same time, all other subscriber stations are blocked because the Ouittungsrückruf from this is evaluated like a foreign selective call. The duration of the transmission is adapted to this. After the transmission of your own phone number to the fixed station is finished, this phone number is available there printed on the fee slip. At the vehicle radio station, after the receipt of the last double acknowledgment tone the mechanical lock on the dial is opened. The fixed station radiates that Official signal off (tone frequency in Morse "a").

The participant can now start voting. When using an eleven-part rotary selector as a scanner, the call number can comprise up to eleven digits. This is the maximum number of digits in a phone number that can be found in the SWFD. The digits are marked in the memory.
The number dialed by the subscriber is then stored in the memory. The sampler is switched on at the output of the memory and forwards the memory settings in chronological order to the low-frequency oscillators when the storage has ended. In order to ensure that the vehicle participant does not intentionally or negligently block the speech channel, the device is switched off, for example by a thermal relay, after transmitting his own call sign, if the participant does not start dialing within 10 seconds. After the start of dialing, this period is extended by 25 seconds so that the number can still be saved. After a total of 30 seconds from the start of dialing, the thermal relay activates the scanner, which in the meantime had run home after transmitting its own phone number. The scanner applies the preset audio frequency circuits in the memory to the LF oscillators, the double tones are sent and acknowledged by the fixed radio station in the same way as when transmitting the own call number by switching the scanner. This procedure achieves the greatest possible security against incorrect selection. At the fixed station, the digits of the phone number can also be registered and printed on the charge slip. You can obtain complete documents about time, callers, called parties and charges if you also print the day and time information on the charge slip. The memory at the fixed radio station / in the transfer device in turn records the double-tone sequence as call number settings and then forwards them to the telephone dialing device in accordance with the frequency. Meanwhile, a waiting signal is broadcast via the transmitter. After the last pulse has been sent, the radio path is interconnected with the wire path. All other tone-frequency characters, such as dial tone or busy tone from the LW of the telephone dial-up connection, are now transmitted directly to the radio subscriber. For the sake of simplicity, when the telephone dialing equipment on the way exits are busy, all of the stored pulses are sent, and the radio subscriber only receives the busy signal afterwards.

During the conversation or at the end of the conversation, the counting pulses come from the /. GW into the charge meter and operate a counter there. The setting of the counter is printed on the charge slip at the end of the call. Additional charges that differ from the charges for the telephone service can be recorded in the charge counter as additional pulses.

The call costs are thus identified as a multiple of the unit of charge.

At the end of the call, the ringing tone is also placed on the radio channel that is used by a If the vehicle is still switched on, it causes it to be thrown.

The device described can also serve to improve the operational safety of the rural road radio selective call method to improve significantly. It is advantageous to choose the one at the fixed station by choosing the telephone network marked selective call automatically with the interposition of the dial tone several times to repeat until the desired vehicle radio station has correctly received the selective call. the Acknowledgment of a correctly received selective call can be done in a simple manner in that the scanner is caused to run through its rotational steps again and the associated Double tones are sent. The sending of the double tones then corresponds to the case of the own call for which each double tone must be acknowledged. It is then again at the fixed station outgoing selective call can only be compared automatically with the original one. In the case of incorrect calls the participant is thrown off.

Dial-up traffic in the direction of the fixed radio station · vehicle radio station is made possible by assigning a code number for the fixed station, which is provided by the telephone subscriber can be controlled. After dialing the code and a free channel, only the selective call number is then available to select the desired vehicle. The billing is through the code number fixed station.

Claims (5)

Patent claims: 1. System for direct dialing of any wired telephone connections from movable ones Radiotelephony systems from which the mobile subscriber as a result of tone combinations transmitted call and dial signals received from a fixed radio station, acknowledged, after storage in normal dial pulses implemented and transferred to the telephone network, characterized in that Each sound combination is broadcast by the vehicle station until one of the same Tone combinations of existing Ouittungstonruf the fixed station the call facility of the Vehicle station automatically to the next combination of the sequence forming the call number advances. 2. System according to claim 1, characterized in that for evaluating the receipt Selective call device intended to set up connections from the fixed to the mobile radio stations is also used. 3. System according to claim 1 or 2, characterized in that automatically the own call number is sent out by the vehicle radio station before the start of the election. 4. System according to claim 1, characterized in that with an incoming selective call a receipt in the form of your own phone number is sent for the vehicle radio station the fixed station in the gateway is compared with the transmitted callsign and, if correct, is used to switch off an automatic selective call repetition. 5. System according to claim 1 or the following, characterized in that for the direction of the vehicle — fixed radio station a frequency series (jj) is set, which is around a certain difference frequency is offset from the usual frequency range of the selective call system. Considered publications: German Patent Specifications No. 878 516, 888 710, 742; French Patent No. 964,887; French additional patent specification No. 58 529 to No. 963 490. 1 sheet of drawings