[Framing error]
A framing error occurs when SPACE is detected at the stop bit. When a framing error or a vertical parity error occurs for the data which is received, the printer prints out a “?” mark to indicate that the error occurred.
[Compulsion switch]
When pin 6 of the peripheral unit drive circuit connector is set “HIGH”, status bit 7 becomes “1”.
2-6-2. X-ON/X-OFF mode
This mode accessed when the DIP switch 3-5 is OFF.
| X–OFF | X–OFF | |
X–ON | X–OFF | X–OFF X–ON | X–OFF | X–OFF X–ON |
TXD
Printing
Paper out signal
ON
ON LINE lamp OFF
Power ON
DataData
Paper out | Load paper and press |
| the ON LINE switch. |
If printer errors do not occur after the power is turned on, the printer outputs an X-ON (DC1 by control code; 11H by hexadecimal data) signal on the TXD signal line which sends it to the host computer. When the host computer receives the X- ON signal, the host computer transmits the data to the RXD signal line for the printer. If data text is not sent from the host computer (even after transmitting the X-ON signal to the host computer), the printer outputs an X-ON signal at 3 second intervals until the printer receives data.
The printer starts outputting an X-OFF (DC3, 13H) signal when the empty space in the buffer reduces below 256 bytes. When the host computer receives the X- OFF signal, it halts output of data. (however, the printer can continue receiving data until the buffer becomes completely full.)
Output of the X-ON signal is resumed when the data in the buffer is printed out and drops to below 256 bytes.
