Appendix A: Serial Interface
A-1. Connectors and Signals
RS-232C
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| Pin no. | Signal name | I/O direction |
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| 1 |
| — |
| Frame ground | ||
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| 2 |
| N/C |
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| Not connected | |
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| 3 |
| RXD | IN |
| Received data | |
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| 4 |
| RTS | OUT |
| Data transmission request signal. This is always | |
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| “SPACE” when the printer is turned on. (Always |
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| “SPACE” status) |
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| N/C |
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| Not connected | ||
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| 7 |
| — |
| Signal ground | ||
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| N/C |
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| Not connected | ||
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| 11 |
| RCH | OUT |
| When the printer is ready to receive data, the signal line | |
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| is same as pin 20. |
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| 12 |
| N/C |
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| Not connected | |
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| 13 |
| GND | — |
| Signal ground | |
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| 14 |
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| OUT |
| When printer error occurs (such as paper out, mechani- |
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| FAULT |
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| cal error, etc.) this signal changes to “MARK”. |
APPENDIX |
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| N/C |
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| Not connected | |||
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| 20 |
| DTR | OUT |
| Data terminal ready signal. When the printer is ready to | |
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| receive data, this signal changes to “SPACE”. |
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| N/C |
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| Not connected | ||
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| 14 |
| 25 | |||
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| 1 |
| 13 |
Fig. A-1 Serial interface connector
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