SU608149A1 - Device for interfacing telegraphy apparatus with computer - Google Patents

Description

connected to the request and control inputs of the device respectively; the first, second, third inputs to the group of inputs of the interrogation unit are connected respectively to the first, second, third outputs of the control unit and to the group of code inputs of the device, and the control unit contains a single vibrator, an OR element and a delay element and the first input of the control unit is connected to the first inputs of the first and second elements I, the second inputs of which are connected to the trigger output, the unit input of which is connected to the third input of the control unit and through the sampler is connected to the first output of the control unit, the zero input of the trigger through the OR element is connected to the fourth input of the control unit and to the output of the second element I, the third input of which is connected to the second input of the control unit, the fourth input of which is connected to the third output of the control unit , and the second output of the control unit is connected to the output of the first element AND, the signal level converter contains a switching element and the element NOT, the output of the signal level converter through the element NOT, and the second input p signal level transducer - through the switching element connected to the first input of the signal level converter.

In addition, the telegraph wiring unit contains a key cascade on the first transistor, with a master circuit in the emitter circuit of this transistor and a key cascade on the second transistor with a relay in the collector circuit, the base of the second transistor connected to the master circuit, and the base of the first transistor through limiting resistor and divider connected to the outputs of the block.

FIG. 1 shows a block diagram of the device; in fig. 2 - a functional diagram of the block connection telegraph apparatus. The device for interfacing the telegraph units with the computing machine contains a switch I, a polling unit 2, a signal level converter 3, a block 4 of a telegraph cable connection 5 pulse generator, a control unit b, a communication line 7, a signal level converter contains a switching element 8 and elements 9, the control unit contains AND 10 elements. P. OR element 12, trigger 13, delay element 14, one-shot 15. The device has a request input 16, a sign (7, control 18, a group of 19 code inputs, information inputs 20, and signs The device output is output 21..

The telegraph connection unit contains a key stage on the transistor 22, a timing chain 23 consisting of a capacitor 24 and a diode 25, a key stage on a transistor 26, a relay 27, a divider consisting of resistors 28, 29 and a limiting resistor 30. The unit can also contain resistors 31-36, a neon light bulb 37, a button 38, a power supply element 39. The positions 40, 41, 42 denote a relay and a telegraph contact, the device, respectively.

The device can be divided into three modes:

- the search mode, which is the initial (duty) mode, in which the device is in the absence of requests for communication from both the computer side and the aboIents;

- request mode from the side of the subscriber, in which the device is transferred, when you press the "Request in one of the telegraph switching unit" button. The transition of the device to this mode is possible only from the search mode;

- request mode by the computer, the transition to which is possible from the already mentioned modes. At the same time, the computer programmatically enters the code of the number of the required telegraph apparatus (TA) in the polling unit, connecting it to the device. The change of the modes of operation of the device is carried out automatically, depending on the specific situation in consideration; moment of time.

At the end of the communication session, the computer sends a signal to the device to “Release, transferring it to search mode.

In the search mode, element nom mutation 8 is open. The polling unit 2 through the element 10 of the block 6 continuously receives pulses from the generator 5. The polling unit 2 can be made in the form of consecutively connected counter and decipher. The counter cycles through 2 pulses (the n-bit counter). During the reference cycle, the decoder of block 2 alternately opens the switch keys producing connection of the corresponding blocks 4 via lines 7 to the signal level converter 3. When eggom in the line 7 of the connected block 4, a current interrogation pulse occurs

When the button “Request 38 (subscriber side request mode) is closed in one of the blocks 4, its input resistance decreases, therefore, when it is connected to the signal level converter 3, the connection line 7 increases, which triggers the HE element 9, which supplies A triggering signal is sent to element I 11. At the same time, the next signal from generator 5 through element AND 10 enters the counter of block 2, and through elements AND AND and OR 12 sets trigger 13 to the state Request, which locks elements 10, 11. In the counter of block 2 is fixed to corresponding block 4. Deschifrator unit 2 will keep v.otkrytom state corresponding to the key switch 1 over an entire session of communication between the computer Ita. Since the time of exposure of the current to the input of block 4 exceeds the interrogation pulse, this leads to its triggering, and, consequently, to connecting the TA to the communication line 7.

The exchange of information between the computer and the TA is carried out in half-duplex mode. When information is transmitted to the TA, in accordance with the code message of the transmitted sign, the communication element 8 is opened or closed, which is controlled by the computer on input 17, which results in a line connection 7 combiatsiya current n best, kovyh parcels. When transmitting information,

the reverse direction as a result of the closing and opening of the contacts of the transmitter TA, the current in the communication line 7 will change in accordance with the code of the transmitted character. The code parcels are perceived by the element NOT 9 of the signal level converter 3 and output 21 enters the computer. The starting sending of each sign transmitted from the TA is perceived by the computer as an interrupt signal.

In the request mode from the computer side, the communication with the TA is performed by software. The computer enters the code of the required block 4 into the counter of polling block 2 on inputs 19. Preliminarily, on input 16, a computer sends a request signal to the device, which switches the trigger 3 to the request via the OR 2 element, and resets to the zero state through the delay element 14 unit 2 counter. In the future, the operation of the device is similar to the work in the request mode from the TA.

At the end of the communication session, the computer generates at the input 18 of the device a “Hang-up” signal that arrives at the initial setting of the trigger 13 n to start the one-shot 15. The one-shot 15 closes the decoder of the block 2 for the time required to convert b; 1 4 to the original condition. When the decoder of block 2 is locked, co-mute 1 disconnects blocks 4 from signal level converter 3. At the counter input in block 2, pulses from the generator 5 again begin to flow. The device returns to the search mode.

The input resistance of block 4 may vary depending on the state of the button Query 38. When short polling current pulses are applied (in search mode) to the input of block 4, the potential from the divider on the resistors 28 and 29 through the resistor 30 P (to: stupid transistor 22, the short-term opening of which does not trigger the key on transistor 26, but their presence at the input of block 4 can be judged by the flashing of the neon light bulb 37.

If the duration of the current pulse at the input of block 4 exceeds the polling, then through the opening of the transistor 22 and the bottom 25 the time of the driving capacitor 24 is charged, the potential of which opens the transistor 26 through a divider on resistors 34 and 35, which causes the contacts 27. A 40 n 41 relay 27 connects the TA 42 to the input of block 4 (for operation in a line) and switches its motor into a power circuit.

Connecting the TA to the communication line 7 from the search mode can be done by pressing the "Request 38" button. This will reduce the input resistance of block 4, which will lead to an increase in the current in the communication line 7, and, consequently, to breaking the element NOT 9 devices. Since, as a result of this, the effect of the current on the input presses the polling pulse in time, block 4 will be triggered.

When information is exchanged between a computer and a TA, OK on line 7, and consequently, at the input, LOCK 4 changes in accordance with the code of transmitted characters. In order to transmit

along line 7 of currentless parcels, but by disconnecting the TA, capacitor 24 is selected so that transistor 26 remains in a saturated state for the time of the maximum possible current parcel. With the current parcels, as a result of the opening of the transistor 22, the charging of the capacitor 24 is performed.

To disconnect the TA from line 7 and turn off its electric motor, it is necessary to feed the current input of the unit to a current-free package that is longer in time, which is carried out by the device upon the request of a computer.

The resistor 32 determines the current value of the neon lamp 37, the variable resistor 31 is needed to adjust the current in line 7, the resistor 36 is for the collector load of transistor 22..

Simplification and increased reliability is achieved by eliminating the triggers, receiving and transmitting relays in all communication channels. The use of half-duplex communication lines in the device allows the subscriber to have one TA, from which he has the opportunity to enter into communication with the computer for working in the dialogue mode. In addition, to connect a subscriber TA to a computer, one current key is enough instead of two used for a duplex communication line. The use of special TA connection schemes allows an increase in the service life of the TA motors and reduce the power consumption from a linear voltage source, since the electricity consumption is practically carried out only during the communication sessions of a computer with subscriber TAs.

Calculations show that the cost of the invention is significantly less than the cost of the known device. This difference increases with an increase in the number of communication channels.

Claims (2)

Invention Formula I. Device for interfacing telegraph devices with a computer, containing a switch, a polling unit, outputs which are connected to the first group of inputs of the switch, a signal level converter, a pulse generator connected to the first input of the control unit, communication channels, the control unit comprising a trigger, first and second elements AND, characterized in that, in order to simplify the device and increase its reliability It contains units for the connection of telegraph devices, the inputs of which are connected to the information inputs of the device, and the outputs - through communication channels with the inputs of the second group of inputs of the switch, the switch output is connected to the first input of the signal level converter, the second input of which is connected to the sign input of the device, the output of the signal level converter is connected to the sign output of the device and the second input of the control unit, the third and fourth inputs of which are connected respectively to the request and to the control inputs of the device, the first, second, third inputs and a group of inputs of the polling unit are connected respectively to the first, second, third outputs of the control unit and to The device has two coaxial inputs, and the control unit contains a one-shot, an OR element and a delay element, and the first input of the control unit is connected to the first inputs of the first and second AND elements, the second inputs of which are connected to the trigger output, the single input of which is connected to the third input of the control unit and through the one-shot - with the first output of the control unit, the zero input of the trigger through the OR element is connected to the fourth input of the control unit and to the output of the second element I, the third input of which is connected to the second input of the unit The fourth input of which is connected via the delay element to the third output of the control unit, and the second output of the control unit is connected to the output of the first AND element, the signal level converter contains the switching element and the NOT element, the output of the signal level converter through the HE element, and the second input -CB-N a signal level converter - through a switching element connected to the first input of a signal level converter. 2. The device according to claim I, characterized in that the unit for connecting the telegraph apparatus contains a key stage on the first transistor with a timing chain in the emitter circuit of this transistor and a key stage on the second transistor from a relay in the collector circuit, the base of the second transistor connected to time is the driving chain, and the base of the first transistor is connected via a limiting resistor to the divider to the outputs of the block. Sources of information taken into account in the examination: 1. USSR Author's Certificate No. 278759, cl. G About F 3/04, 1970. 2. Bazilevich E. V., Pramnek G. F. Message Switching Systems Based on Computer Techniques. Link, 1971, p. 21, fig. 1.6.