The printer interface device of multiple users share
Technical field
The utility model relates to a kind of printer interface device, and especially a kind of printer interface device for multiple users share belongs to the printer technology field.
Background technology
At present, existing printer is as peripheral product, and major part only is equipped with a communication interface (serial ports, parallel port or USB mouth), is used for carrying out exchanges data with PC or terminal.Therefore, print out task is finished in the instruction that can only accept a main frame of printer.Though being equipped with two or more communication interfaces (serial ports, parallel port or USB mouth), the printer that has to carry out exchanges data with host PC or terminal.But such printer, owing to can't differentiate the data of different printing interfaces, the data that distinct interface can not be received all are placed in the same buffer to be handled, and allow plural interface all work, so can not accept the instruction of two or two above main frames simultaneously prints, otherwise can cause the print data disorder, cause the printer can't operate as normal.That is to say,, but still can only use one of them interface to finish print out task though such printer provides two or more communication interfaces.Therefore, present printer interface can not satisfy the requirement of multiple users share printer.
Summary of the invention
For overcoming the requirement that the existing printer interface can not satisfy a printer of multiple users share, the utility model provides a kind of printer interface device of multiple users share.Can allow the multi-user to be many main control computers by different printer communication interfaces share and use a printer.
The utility model solves the problems of the technologies described above the scheme that is adopted: a kind of printer interface device of multiple users share, comprise the CPU main control board and on the serial ports of the basic communication interface of conduct, it is characterized in that being connected with outside plug type expansion interface circuit plate by the interface socket on the CPU main control board.To realize the expansion of second communication interface.
Described outside plug type expansion interface circuit plate is provided with the serial ports that matches with serial ports on the main control board, perhaps parallel port, and perhaps USB mouth, perhaps a serial ports adds a USB mouth, to realize multi-user's purpose of a shared printer simultaneously.
Described serial ports drives chip with the RS-232 level conversion and links to each other, so that serial ports can be worked alone.
Described parallel port links to each other with interface circuit, so that the parallel port can be worked alone.
Described USB mouth links to each other with interface conversion circuit, so that the USB mouth can be worked alone.
The utility model compared with prior art has following advantage and effect: adopt such scheme, for printer provides various communication interfaces, simultaneously also provide multiple interfaces to be used in combination mode, can come from which communication interface by recognition data, thereby discern the print out task of different main frames, satisfy the multi-user and share the requirement of using printer simultaneously.
Description of drawings
Fig. 1 is a structural representation of the present utility model;
Fig. 2 is the serial port circuit schematic diagram of outside plug type interface expansion board of the present utility model;
Fig. 3 is the parallel port circuit theory diagrams of outside plug type interface expansion board of the present utility model;
Fig. 4 is the USB mouth circuit theory diagrams of outside plug type interface expansion board of the present utility model.
The specific embodiment
Below in conjunction with accompanying drawing the utility model is described further.
Among Fig. 1, outside plug type expansion interface circuit plate 1 links to each other with interface socket 4 on the printer master control borad 5 by socket 2, to realize the expansion of second communication interface.
Among Fig. 2, socket 2 on the outside plug type expansion serial port circuit plate 1 is by the TX holding wire, the RTS holding wire, the DTR holding wire links to each other with 1488 electrical level transferring chip 6, this chip links to each other with computer by RS-232 interface 7, interface socket 4 on the printer main control board 5 links to each other with the socket 2 that outside plug type is expanded on the serial port circuit plate 1, RX holding wire by socket 2 correspondences, cts signal line and DSR holding wire link to each other with 1489 electrical level transferring chip 8, this chip links to each other with another computer by RS-232 interface 7, thereby realizes that the multi-user shares the purpose of same printer simultaneously.Present embodiment uses 1488 and 1489 as the electrical level transferring chip that send and receive the RS-232 signal, is sent to the signal RX of printer by PC, and CTS and DTR are converted into Transistor-Transistor Logic level by 1489 with the RS-232 level and deliver to CPU; Send to the signal TX of PC by printer, RTS and DTR are converted to the RS-232 level by 1488 with Transistor-Transistor Logic level and send to PC.The signal of the first serial of present embodiment is directly delivered to CPU and is handled on the CPU master control borad; The signal of second serial is transferred on the CPU master control borad by the interface socket 4 on socket 2, the master control borad 5, just utilizes outside plug type interface board expansion second serial.
Among Fig. 3, socket 2 on outside plug type expansion and the interface circuit board 1 links to each other with 74HCT245 chip 9 by eight bit data holding wire D0-D7, this chip links to each other with computer by IEEE-1284 interface 10, socket 2 on outside plug type expansion and the interface circuit board 1 is again by handshake ACK line, the BUSY line, the PE line, the PFAULT line, the SELECT line links to each other with LS241 chip 11, the socket 2 of interface socket 4 on the printer main control board 5 on outside plug type expansion and interface circuit board 1, by handshake INIT line, 1284 lines, the AUFD line, the STROBE line links to each other with LS241 chip 11, S241 chip 11 links to each other with another computer by IEEE-1284 interface 10, thereby realizes that the multi-user shares the purpose of same printer simultaneously.The data direction that present embodiment uses 74HCT245 chip 9 to control two-way parallel port is to send to printer or printer sends to PC by PC.Use LS241 chip 11 to be handshake ACK, BUSY, PE, PFAULT, SELECT, INIT, 1284, AUFD provides the function of strengthening driving.The parallel port signal is transferred on the CPU master control borad through the interface socket on the master control borad 54 by socket 2.
Among Fig. 4, socket 2 on the outside plug type expansion USB interface circuit board 1 is by eight parallel-by-bit data signal line D0-D7, handshake ACK line, the BUSY line, the PE line, the PFAULT line, the SELECT line links to each other with PL2305 chip 12, the socket 2 of interface socket 4 on the printer master control borad 5 on outside plug type expansion USB interface circuit board 1, by handshake INIT line, 1284 lines, the AUFD line, the STROBE line links to each other with PL2305 chip 12, PL2305 chip 12 by usb 13 respectively with computer PC data-signal D+, D-links to each other, thereby realizes that the multi-user shares the purpose of same printer simultaneously.In the present embodiment, by USB interface chip PL2305 8 parallel-by-bit data of the usb data of PC end and printer side are carried out implementing transmission after the protocol conversion of IEEE1284-USB2.0.PL2305 is the USB interface that meets the USB2.0 protocol specification for the PC end, is the parallel port that meets the IEEE1284 agreement for printer side.The parallel port signal is transferred on the CPU master control borad through the interface socket on the master control borad 54 by socket 2.