Parallel interface signals
The following table provides details for the signals used on the printer’s parallel interface. Note descriptions in [ ] are for
Signal | Meaning |
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Strobe* [nStrobe] (Pin 1) | A | |
| the data on the Data 0 [1] to Data 7 [8] signal lines. | |
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Data 0 [1] to Data 7 [8] | These eight signals form the data byte sent from the host computer to | |
(Pins 2 to 9) | the printer. Data 7 [8] is the most significant bit and Data 0 [1] is the | |
| least significant bit. | |
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Acknowledge* [nAck] | This signal is returned to the host computer. This | |
(Pin 10) | acknowledges the previous character received by the printer. | |
| Acknowledge* pulses are sent only when Busy is low. | |
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Busy [Busy] (Pin 11) | This signal is returned to the host computer. This signal is high when |
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| the printer is busy and low when it is able to accept more data. Every | |
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Paper Empty [PError] | This signal is returned to the host computer. This signal goes high | |
(Pin 12) | when the printer runs out of paper. | |
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This signal is returned to the host computer. This signal is high when | ||
| the printer is | |
| when the upper unit is raised, or when the Go key is pressed to set the | |
| printer | |
| Note: The Paper Empty and | |
| enabled by the FRPO command (O2 parameter). | |
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This signal is used in the Epson version of the Centronics interface to | ||
(Pin 14) | receive a carriage return. In | |
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+5 V DC (pin 18) | This line is connected to the printer’s +5 V DC line (+5 V ±0.5 V, 400 |
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| mA maximum, fused). | |
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Prime [nInit] (Pin 31) | This signal is used in the standard Centronics interface to enable the | |
| computer to reset the printer. It is ignored by the printer. | |
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Error* [nFault] (Pin 32) | When the | |
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| line returns error status to the host computer. | |
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Auxiliary output 1 (Pin 33) | This signal line is not used. | |
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Power Ready (Pin 35) | This signal is high when the printer’s power is on. | |
Select In [NSelectIn] | This signal is used in some versions of the Centronics interface to | |
| enable the computer to force the printer | |
| it is used as an interrupt. | |
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