SU1388878A1 - Device for interfacing subscriber with communications link - Google Patents

Abstract

The invention relates to computing and can be used in systems for the exchange of information between a computer and a remote external device. The purpose of the invention is to increase the reliability in the exchange of information through hardware control. The device contains a receiving node, a transfer node, a shift register, four triggers, two modulo-two adders, a comparison element, two one-shot, a pulse generator, two groups of elements I. 4 ill.

Description

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The invention relates to computing technology and can be used in systems for the exchange of information between a computer and a remote external device, such as a display.

The purpose of the invention is to increase the reliability in the exchange of information through hardware control.

. Figure 1 shows the block diagram of the proposed device; FIG. - diagram of a phase-modulated waveform generator; on fig.Z - the implementation scheme of the decoder; FIG. 4 shows a waveform of signals in a communication channel.

The device (Fig, 1) contains a shift register 1, the second 2 and the first 3 counters, the first group of elements AND 4, the third trigger 5, the first 6, the second 7 and the fourth 8 triggers, receiving node 9, transfer node 10, pulse generator 11, information input 12 information input-output 13, the first 14 and second 15 modulo-two adders, the comparison element 16, the first 17 and the second -18 one-shot, the second group of elements And 19, the information output 20, strobe1: rui11tsii input 21, the first synchronous input 22 reception, the installation input 23, the second synchronous input 24 reception.

Node 9 of the reception (figure 1) contains the amplifier-receiver 25 and the decoder 26.

The transmission unit 10 (FIG. 1) comprises a transmitter-amplifier 27 and a phase-modulated driver 28. ,

Shaper 28 phase-modulated signals (figure 2) contains a shift register 29, the element AND 30 and the switch 31.

The decoder 26 (FIG. 3) contains the AND-HE elements 32-35, the triggers 36 and 37, and the element OR 38.

The node 9 is designed to receive and convert the signals coming from the communication channel. Amplifier receiver 25 converts the sequence of signals coming from the channel 13 from the communication channel into two sequences of pulses corresponding to positive and negative half-periods of the signal. The decoder 26 generates synchronization pulses from the two pulse sequences and extracts the logical units of information that arrive at the shift register 1.

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The node 10 is designed to form phase-modulated signals and transmit them via bus 13 to the communication channel.

Counter 2 is designed to count synchronization pulses applied to shift register 1.

Shift register 1 is designed to convert serial code into parallel and vice versa.

Counter 3 and trigger 6 form a timer designed to track exchange time intervals.

The groups of elements 4 and 19 are multi-buffer buffer amplifiers for coupling to a main line of a computer.

A single-oscillator 17 generates a rewriting pulse in counter 2. Modulators 14 and 15 are modulo-designed to form control bits in the transmission and reception of information.

Comparison element 16 serves to compare check bits when receiving information from a communication link.

The device works as follows.

Information is exchanged between the computer and an external device, such as a display, via a two-wire line, such as a coaxial cable. The signals emitted to the communication channel and received by it are two-field, phase-modulated. By command

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The computer generates a general reset signal on bus 23. In this case, a trigger 7 is set in the device and one-shot 17 and 18 are started. The one-shot 17 carries out a preliminary recording in counter 2, and its conversion factor is set. The one-shot 18 causes reset of the trigger 5 Ready receiver and 5 of the trigger 8 Timer failure.

The reset signal is also fed to the receiving node 9, fed through the bus 22, this opens the group of elements AND 19 and reads the state of the triggers 5, 7 and 8 and the comparison element 16, which form the device status register. After analyzing the state register of the device, if the trigger 7 is set to be ready for transmission, information is written to the shift register 1 via the bus 12 pulses through the bus 21. The trigger 7 is reset, allowing operation of the

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Rovatel 28 phase-modulated signals.

The shift register 29 and the element AND-30, included in the driver 28 (Fig. 2), form four series of pulses shifted relative to each other for the period of the generator frequency. The first and second series are used to form a signal. The switch 31 connects to the amplifier-transmitter in pairs the first and second or second and first outputs of the shift register, respectively, if 1 or O is received, to the control input of the switch. From the output of the pulse transformer of the amplifier-transmitter, bipolar pulses are transmitted to the communication channel. Thus, the serial code from the output of the shift register 1 controls the switch of the driver 28. The two-field signal also goes to the input of the receiving node 9. Amplifier receiver 25 amplifies the signal and forms two sequences of pulses corresponding to the positive and negative half periods of the input signal. These two sequences are fed to the input of decoder 26. The operation of the decoder is to derive a synchronization signal and information bits from two sequences of pulses. Consider the work of the decoder when a single bit is received from a communication channel.

At the initial time, the triggers are reset to zero by a reset signal, therefore, AND-NOT elements 32 and 33 are open. The impulse corresponding to the positive half-period arrives at the first input of the decoder 26 and sets the trigger 36. At the same time, the AND-HE element 33 is closed and the AND-HE element 34 is opened. The impulse, corresponding to the negative half-period, is fed through the AND-HE elements 34 and OR 38 sync output node 9 reception. The falling edge of the same pulse resets the trigger 36. Information is written to the shift register 1 on the leading edge from the single output of the trigger 36, which is the information output of node 9. Thus, the decoder presented in the variant of receiving node 9 operates (Fig. 3).

On this cycle, the transfer of one cum ends. Sprinkle length

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determined by the conversion factor of counter 2. When sending parcels, trigger 5 the receiver for transferring counter 2 is not set, since the information input of this trigger is set low from the output of trigger 7. Reception of information from the communication channel is carried out similarly. In this case, Lena 1 is set at the information input of trigger 5, and upon receipt of the transfer from counter 2, the Ready receiver indicator is set. In order to increase the reliability of the received information during transmission, a check bit is generated by modulo 14 adder 14. After receiving the parcel, the check bit is generated modulo two by the adder 15, and the generated and the received check bit are compared by the comparison element 16. The result of the comparison goes to the status register. By analyzing the status register, you can determine the presence of a failure. According to the requirements of the interfaces, it is necessary to determine not only failures, but also to hold the specified time intervals when executing the exchange operations. For these purposes, the timer is built on counter 3 and trigger 6. When recording, for example, instructions to the shift register 1 for transmission to an external device at the information input of trigger 6 is set to 1. The trigger sets and allows the counter 3 to work. the same clock pulse records the number. On the synchronous input of the counter 3, subtractive im-, pulses are received. Transfer counter 3 sets the trigger 8 Timer failure. But if a parcel is received from the external device earlier, when the trigger 5 is set, the ready receiver trigger 6 is reset and prohibits the operation of counter 3. When reading the state register, the one-shot 18 starts and resets the Ready and Fault triggers. timer

Formula of an Invention Device for connecting a subscriber to a communication channel, comprising a receiving node, a transmission node, a shift register, two counters, four triggers, a pulse generator, the first group

And elements, the first indicator, and the information input of the receiving node and the information output of the transmission node form the device's input-output for connection to the communication channel, the first information input of the shift register, the information inputs of the first counter and the first trigger form a group of device inputs for connection to the information group the subscriber's outputs, the installed input of the receiving node is connected to the start input of the first one-shot, to the single input of the second trigger — and is the input of the device for connection to subscriber’s output, the write register entry is connected to the first counter record input, the first trigger is synchronized, the second trigger has zero input and is the device input for connecting to the subscriber's gate output, the output group of elements I of the first group forms the output group of the device for connecting to the group of information inputs of the subscriber, while the first inputs of elements AND of the first group are connected to the group of information outputs of the shift register, the second information input of which is soy Inen with the information output of the receiving node, the sync output of which is connected to the counting input of the second counter and the synchronization code of the shift register, the information output of which is connected to the information input of the transmission node, the synchronous input of which is connected to the output of the pulse generator and the counting input of the first counter, the installation input of which is connected to the output the first trigger, the zero input of which is connected to the output of the third trigger, whose information is connected to the installation input of the transmission node and to the output of the second trigger, the synchronous input of which is connected to the synchronous input of the third trigger, with the enable input of the first one-oscillator and the output of the second counter, the recording input of which is connected to the output of the first one-oscillator, characterized in that, in order to increase the reliability of information exchange due to hardware control, it is entered two modulo adders, second AND group, element

comparison, the second one-shot, and the permitting input of the second one-shot is connected to the first inputs of the elements of the second group and is the input of the device for connecting to

5, the first synchronization output of the subscriber, the second inputs of the And elements of the first group are the input of the device for connection to the second synchronization output of the subscriber,

0 outputs of elements And the second group are connected to the group of outputs of the device for connection to the group of information inputs of the subscriber, the group of inputs of the first modulo adder

5 two are connected to the device input group for connecting to the subscriber information output group, the start input of the second one-shot is connected to the device input for connecting to the subscriber's installation output, while the second inputs of the AND elements of the second group are connected to output-. For the second, third, fourth, trigger element, the output of the first counter is connected to the single input of the fourth trigger, the zero input of which is connected to the zero input of the third trigger and the output of the second one-vibrator; the output of the first modulo-two adder is connected to the first information input of the Shift register , the group of information outputs of which is connected to the group of inputs of the second modulo torus sum, the output of which is connected to the first input of the comparison element, the second input of which is connected to the controller ldny discharge group of information soda shift register.

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Claims (1)

Claim A device for pairing a subscriber with a communication channel, comprising a receiving unit, a transmission unit, a shift re- ₍ histr, two counters ^, four triggers', a pulse generator, a first group of AND elements, a first one-shot, and the information input of the receiving unit and the information output of the transmitting node form the input-output of the device for connection to the communication channel, the first information input of the shift register, the information inputs of the first counter and the first trigger form the group of inputs of the device for; connect to the group of information outputs of the subscriber, the installed input of the receiving node is connected to the start input of the first one-shot, with a single input of the second trigger. And is the input of the device for connecting to the installation output of the subscriber, the input of the shift register record is connected to the recording input of the first counter, with the clock input of the first trigger, with the zero input of the second and a trigger input device ^connected! Nia strobe output to the subscriber, the group of outputs of aND gates of the first group forms a group of outputs of the device for connection to a group of information nnyh subscriber inputs, with the first entry! elements And of the first group are connected to the group of information outputs of the shift register, the second information input of which is connected to the information output of the receiving unit, the clock output of which is connected to the counting input of the second counter and the clock input of the shift register, the information output of which is connected to the information input of the transmission unit, the sync input of which is connected to the output of the pulse generator and with the counting input of the first counter, the installation input of which is connected to the output of the first trigger, the zero input of which connected to the output of the third trigger, the information input of which is connected to the installation input of the transmission unit and to the output of the second trigger, the sync input of which is connected to the sync input of the third trigger, with the enable input of the first one-shot and to the output of the second counter, the recording input of which is connected to the output of the first one-shot, characterized in that, in order to increase reliability when exchanging information through hardware control, two adders are introduced into it modulo two, the second group of AND elements, the comparison element, a second one-shot, and the allowing input of the second one-shot is connected to the first inputs of the AND elements of the second group and is the input of the Device for connecting to the first output of the synchronization of the subscriber reception, the second inputs of the elements of the first group are the input of the device to connect to the second output of the synchronization of the subscriber reception, the outputs of the elements AND the second group are connected to the group of outputs of the device for connecting to the group of information inputs of the subscriber, the group of inputs of the first adder modulo two is connected to the group inputs of the device for connecting to the group of information outputs of the subscriber, the input * of the start of the second one-shot is connected to the input of the device for connecting to the installation output of the subscriber, while the second inputs of the elements of the second group are connected to the output -. by the second, third, fourth triggers, the comparison element, the output of the first counter is connected to the single input of the fourth trigger, the zero input of which is connected to the zero input of the third trigger and to the output of the second one-shot, the output of the first adder modulo two is connected to the first information input of the shift register, the group of information the outputs of which are connected to the group of inputs of the second adder modulo two, the output of which is connected to the first input of the comparison element, the second input of which is connected to the control p zryadom group of information outputs of the shift register. FIG. 2 To receiver linear signals Figl Log'G Log ''! ” Log ’(G Log * O * t fa 1 " Fig 4