Appendix D: Serial Interface (RS-232C)
D-1. RS-232C Connector
Pin No. | Signal name | Direction | Function | ||
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25 Pin | 9 Pin |
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1 |
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| — | Frame ground | |
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2 | 3 |
| TXD | OUT | Transmission data |
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3 | 2 |
| RXD | IN | Receive data |
4 | 7 |
| RTS | OUT | Same as DTR signal. |
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5 |
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| N/C |
| Not used |
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| 8 |
| CTS | IN | Status of this signal is not checked. |
6 | 6 |
| DSR | IN | STAR Mode |
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| Status of this signal is not checked. |
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| ESC/POS Mode |
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| In DTR/DSR communication mode, indicates whether data receive |
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| from host is enabled or disabled. |
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| Space: Receive enabled |
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| Mark: Receive disabled |
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| (except when transmitting data by DLE EOT, and GS a) |
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| This signal is not checked in the |
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| mode. |
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7 | 5 |
| — | Signal ground | |
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8~19 | 1,9 |
| N/C |
| Not used |
20 | 4 |
| DTR | OUT | STAR Mode |
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| Indicates whether data receive from host is enabled or disabled. |
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| 1) DTR/DSR Communication Mode |
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| Space when receive is enabled. |
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| 2) |
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| Always space, except during following conditions: |
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| • Period between reset and communication enabled |
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| • During self printing |
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| ESC/POS Mode |
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| Indicates whether data receive from host is enabled or disabled. |
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| 1) DTR/DSR Communication Mode |
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| This signal indicates whether the printer is busy. SPACE |
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| indicates that the printer is ready to receive data, and MARK |
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| indicates that the printer is busy. The busy condition can be |
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| changed by using DIP SW |
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– 39 –
