Citizen Systems CBM-710/720 service manual Serial Interface Circuit

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CBM-710/720 Service Manual

8.Serial Interface Circuit

As the serial interface specification, RS-232C and 20 mA current loop can be switched by the slide switch. It can be switched by the user although fixed by setting at delivery time.

1)RS-232C

By using MAX232C for data receiving (RD), data transmitting and BUSY (DTR), data is transmitted and received at level of RS-232C. The baud rates of 110 to 9600 bps can be selected by switching the DIP switch.

2)20 mA Current Loop

The photo coupler is used for transmitting and receiving. The photo coupler LED is used for receiving data and the photo transistor for transmitting data.

3)DIP Switch Reading

The baud rate, word length, parity check, parity condition are set by the DTP switch.

4)Positive/Negative Power Supply for RS-232C

±12 V power supply is required for obtaining RS-232C voltage level. In this printer, however, as IC MAX232C for interface is used, ±12 V is generated at the power circuit built in IC. Thus, no other power supply is required.

The serial interface circuit diagram is shown in Fig. 8-1.

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Contents DOT Matrix Printer Contents Chapter Printer Disassebly and Assembly How to the Upper Cover and Rear Cover How to Remove the Printer Mechanism How to Remove the Control BoardHow to Remove the Power Board and AC Power Unit How to Remove the Auto Cutter Unit How to Remove the Operation Panel Board and PE Sensor BoardChapter Circuit Description Block Diagram OutlineCPU Peripheral Circuits CPU and ROM/RAM CircuitPower Failure Interrupt Circuit and Initial Resetting Printer Control Circuit Printer Control CircuitCutter Control Circuit Normal Reverse StopInterface with Operation Panel Operation Panel CircuitPaper End Sensor Circuit Paper End Sensor CircuitParallel Interface Circuit STBParallel Interface Circuit Serial Interface Circuit Serial Interface Circuit Diagram RS422A Interface Circuit RS422A Interface CircuitPower Circuit Power Supply CircuitChapter Auto Cutter Maintenance and Handling Mechanism and Principle of Operation Cam Switch Cutter Gear Repairing Troubleshooting Page Disassembly/Assembly Page Chapter Circuit Diagram Power Supply Circuit Diagram CBM710/720-001-00 Noise Filter Circuit Diagram CBM710/720-002-00 Paper End Sensor Circuit Diagram CBM710/720-004-00 Circuit Diagram Parallel Circuit Diagram RS232C CBM710/720-008-00 Chapter Parts List Parts List Exploded View CBM-710/720Ref. No Parts No Description CBM-710,720 CBM-710 CBM-72037 Block Diagram CBM-710/720 Block Diagram Power Supply Unit CBM-710/720 PC Board Noise Filter Unit CBM-710/720 Parts Position Noise Filter Unit Control Board Assy RS232C CBM-710/720 Parts List Control Board Assy RS232C OSC Parts Position Control Board Unit RS232C Control Board Assy Parallel CBM-710/720 Parts List Control Board Assy Parallel Parts List Control Board Assy Parallel Parts Position Control Board Unit Parallel Control Board Assy RS422A CBM-710/720 Parts List Control Board Assy RS422A OSC Parts Position Control Board Unit RS422A Operation Panel Unit Parts Position Operation Panel Unit Parts Position PE Detector Unit OP Junction Block Auto Cutter AC-2/AC-3 AC-2 AC-3AC-2 AC-3 Winder AW-2 AW-2