CN2141105Y - Answer terminating machine - Google Patents

Abstract

The utility model relates to an answer terminating machine for the electromechanical teaching system of a computer, comprising a casing containing a circuit construction plate and the circuit construction plate. The answer terminating machine is arranged on the circuit construction plate. The circuit comprises a keyboard, a CPU, an address latch, a read-only memory, and an interface expander, a display device, a drive device, and a communication interface. A terminal isolation device is provided between the communication interface and the CPU via the circuit for preventing the circuit interference among multiple terminal machines.

Description

Answer terminating machine

The utility model relates to a kind of terminal device that is used for the computing machine Education Literature System, and particularly this system uses replys terminating machine.

The existing terminating machine of replying that is used for computer teaching system has various ways, and for example the standard computer network type is replied terminating machine, carried single card microcomputer formula terminating machine that interface communicates and the additional RS422 of unit or the communication of RS232 interface board and reply terminal etc.The unit volume that the standard computer network type is replied terminating machine is big, the circuit complexity, and it is too high to constitute the networked system cost, is not suitable for common electronic teaching and uses; The single card microcomputer formula answering machine that carries interface can only realize two same answering machine unit dialogues, is not suitable for equally by many tutoring systems of replying terminal of a central main control system control; Unit exists to require order wire quantity big with addition of the terminating machine of replying of RS422 or RS232 interface board mode, and the high shortcoming of supply voltage.

The purpose of this utility model is the shortcoming that exists in the above-mentioned prior art for overcoming, the terminating machine of replying that isolation performance is good between the machine of a kind of multiple terminals, circuit is simple, cost is low and easy to use is provided, this terminating machine can multimachine (for example 250 station terminal machines) simultaneously and an online use of central main control system, talk with separately with main frame, and do not exist the circuit between the terminal to crosstalk, can arbitrarily change response content, main frame can be done various statistics, storage and demonstration.

According to the terminating machine of replying of the present utility model, comprise a shell that constitutes by dial hood and end box, circuit structure plate in the enclosure is set, dial hood is provided with display window and operating key opening, the circuit structure plate is provided with this circuit of answering circuit and comprises: keyboard, CPU (central processing unit) (CPU), address latch, read-only memory (EPROM), the interface extender, display driver, display, time base circuit, automatic reset circuit and communication interface, between CPU (central processing unit) and communication interface, also be provided with the terminal isolator, crosstalk in order to prevent the circuit between many station terminals machine.This terminal isolator is made of two triple gates and a phase inverter, directly be connected with the versatile interface of CPU (central processing unit), directly control by CPU (central processing unit), constitute serial communication mode, make the central main control system in the system become man-to-man control to a plurality of controls of replying terminating machine, thereby solved the circuit isolating problem between many station terminals machine, make a main frame can not have with crosstalking control nearly 250 reply terminal.Because the triple gate buffer circuit is simple in structure, cost is low, can reach the isolation effect that the standard computer network type is replied terminal equally, so be specially adapted to reply terminating machine as the student of the computing machine Education Literature System in the school.

In conjunction with the accompanying drawings embodiment of the present utility model is done detailed being described below.

Fig. 1 is the inclined shaft side view that the utility model is replied terminating machine.

Fig. 2 is the plan view that terminating machine takes off dial hood of replying shown in Figure 1.

Fig. 3 is the functional-block diagram of replying terminating machine according to the utility model.

Fig. 4 is the circuit theory diagrams of replying terminating machine according to the utility model.

See figures.1.and.2, wherein Fig. 1 shows the main body surface structure that the utility model is replied terminating machine, and Fig. 2 has expressed the circuit component geometry arrangement of circuit structure plate.As shown in the figure, reply terminating machine 100 and comprise a shell 1 that holds circuit structure plate 7, this shell is made up of end box 3 and dial hood 2, dial hood 2 is provided with display fenestra 5, its position is corresponding to being arranged on display 2 on the circuit structure plate 7 and 13 position, the upper right side of the transparent cover plate of display fenestra 5 is printed with respectively and 5 light emitting diodes (LED) of display 13 corresponding " A, B, C, D, E " printed words, also be provided with on the dial hood 2 with circuit structure plate 7 on the keyboard 11 corresponding keyboard openings installed, to stretch out 8 buttons of keyboard 11.Multi-core cable wire 9 extends to by the breach that is arranged on end box beyond the shell, and the termination in its shell has multi-core socket 8, and the multi-pin connector 6 through being arranged on the circuit structure plate 7 is connected with the host interface of tutoring system.Whole circuit components of replying terminal are installed on the printed circuit board (PCB) of circuit structure plate 7, comprise display 13 and other corresponding circuit component of 12,5 light emitting diodes formations of display that 11, three light-emitting nixie tubes of keyboard constitute.

Illustrate according to circuit structure of replying terminating machine of the present utility model with reference to Fig. 3 and Fig. 4.As shown in Figure 3, this circuit comprises the keyboard SW1 that imports response message, CPU (central processing unit) (CPU) IC1, address latch IC2, read-only memory (EPROM) IC3, interface extender IC4, show inquiry message and response message display and driver thereof, cooperate the corresponding circuit of the normal operation of center processing unit, as time base circuit and automatic reset circuit, reach the communication interface that connects with the tutoring system main frame.Also be provided with a terminal isolated location between the communication interface of this circuit and the center processing unit, crosstalk mutually in order to prevent that a plurality of terminating machines are operating, as shown in Figure 4, CPU (central processing unit) IC1 has four groups of input/output ports, wherein the P1 mouth is used as the keyboard input port, SW1 is connected with keyboard, and receives+the 5V power supply through pull-up resistor R1, and keyboard SW1 is used for keying in user-selected fixed response message.P0 mouth and P2 mouth are used as address date mouth line, and the P0 mouth is parallel to be connected to address latch IC2, ROM (read-only memory) IC3 and interface extender IC4, and the P2 mouth has a Tiaokou line connection interface extender IC4 in addition.Another group input/output port is multi-functional mouthful, is used for functions such as serial communication, time-base signal is imported and automatically reset.The CPU (central processing unit) IC1 of present embodiment selects 8031 single-chip microcomputers for use, with the integrated circuit 74LS373 of low-power consumption as address latch IC2, it is one eight a bit address latch, can satisfy the utility model and reply the requirement of terminating machine, read-only memory IC3 is used for storing whole software programs of this terminating machine, it is integrated circuit 2764 that the present embodiment is selected model for use, for adapting to the needs of many mouthfuls of lines of display, adopt interface extender IC4 to expand output interface, also increased by 256 byte RAM simultaneously, expanded the capacity of random memory, the delivery outlet line PA of interface extender IC4, PB and PC receive display driver IC 5-IC8 respectively, show main frame enquirement information and user answer information with driving display, display driver is selected low power consumption integrated circuit 74LS04 in the present embodiment for use, they are respectively through current-limiting resistance R2, R3, R4 and R5 drive 7 sections light-emitting nixie tube L pipes, LD2, LD3 and 5 LEDs, the interface extender IC4 in the present embodiment selects for use interface chip 8155 to bear.

The 6th conventional automatic reset circuit that constitutes by R6, D1, C3 and IC8 is connected to CPU (central processing unit) IC1 function corresponding mouth line, for IC1 provides auto-reset function.The time base circuit that is made of crystal oscillator XL and frequency stabilization capacitor C 1, C2 is produced the clock signal of this terminal for IC1 provides the time-base signal of 6MHZ by the internal oscillator of IC1.

Two Tiaokou line PL1-1, the PL1-2 of communication interface PL1 be respectively as the descending and uplink communication interface line between terminating machine and system host, and connect through terminal isolator and the multi-functional mouth of IC1 mouth line mutually.The two other mouth line PL1-3 of communication interface is connected with terminal as the input interface line of the 5V power supply of terminating machine with PL1-4.

The terminal isolator that is used as circuit isolation between the terminal is by triple gate IC9-1, the 5th gate inverter IC7-5 of IC7 in IC9-2 and the driver constitutes, the upstream Interface line PL1-2 of the input terminated communications interface of IC9-1, multi-functional mouthful the delivery outlet line (TXD) of its input termination IC1, and the output terminal of control termination inverter ic 7-5, the input end of IC7-5 inserts the multi-functional mouthful of line T1 of IC1, the downstream interface line PL1-2 of the input terminated communications interface of triple gate IC9-2, multi-functional mouthful the input port line (RXD) of its output termination IC1, and control end ground connection.

When many such terminating machines insert in the tutoring systems with the main frame on-line Application, the inquiry message signal that central authorities' main control system sends is imported CPU (central processing unit) IC1 by the down going port line PL1-1 of communication interface through the terminal isolator, treated by interface extender IC4 output corresponding driving signal, drive seven sections light-emitting nixie tube display LD1-LD3 via driver IC 5-IC7 and demonstrate inquiry message topic number, the response message that the user selectes is keyed in CPU (central processing unit) IC1 by " A-E " of keyboard, drive corresponding one or more LEDs of replying symbol after treatment and light, showing that fenestra shows corresponding character.Simultaneously, the response message of key entry deposits the RAM in the terminating machine in.The user can utilize button N, the L of keyboard to key in modify instruction, and can further pass through the selected response message of information button " A-E " hack, and the response message that main frame can be fetched terminating machine at any time carries out necessary processing.

Be understood that, can make various modifications to embodiment of the present utility model for the person of ordinary skill of the art, but all should belong to design category of the present utility model.

Claims (4)

1, a kind of terminating machine of replying that is used for the computing machine Education Literature System, comprise the shell that accommodates the circuit structure plate, be equipped with on the circuit structure plate and reply the terminating machine circuit, described circuit comprises: the keyboard of keying in response message, CPU (central processing unit), address latch, the read-only memory of storing software program, display and drive unit thereof and with the communication interface of tutoring system serial communication, the address date mouth line of CPU (central processing unit) is parallel to be connected, it is characterized in that between the CPU (central processing unit) of described circuit and communication interface, being provided with the terminal spacer assembly, parallelly between display driver and CPU (central processing unit) be connected with an interface extender in order to increase interface quantity and RAM byte.

2,, it is characterized in that the terminal spacer assembly is made of two triple gates and a phase inverter according to the terminating machine of replying of claim 1.

3, according to the terminating machine of replying of claim 2, the input end that it is characterized in that one of described two triple gates is connected with a delivery outlet line (TXD) of multi-functional mouthful of CPU (central processing unit) and the up going port line of communication interface respectively with output terminal, the output terminal of its control termination phase inverter, the input end of phase inverter is connected with a Tiaokou line of multi-functional mouthful of CPU (central processing unit); On multi-functional mouthful the input port line (RXD) of down going port line that another input end of described triple gate and output terminal are connected respectively to communication interface and CPU (central processing unit), its control end ground connection.

4,, it is characterized in that described display is made up of three seven sections light-emitting nixie tubes and 5 light emitting diodes according to the terminating machine of replying of claim 1.

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