Epson 420i - Manual (Page 31)

3. ETXlACK Protocol
The printer sends an ACK (O6HEX) to the computer in response to the data block
separated by ETX (03HEX) which was sent by the computer. If the communication
buffer space goes below 4K bytes, ACK is not sent. If the buffer space is more than
4K bytes, ACK is sent through the TR line. The ACK’s output data format is the same
structure as the input data.
Baud Rate
The following four baud rates are selected by DIP switches,
Data Length 7/8 Bit Selection
A 7 bit or 8 bit data length may be selected by DIP switch 1-3. When the switch
is ON, the 7 bit length is selected. When the switch is OFF, the 8 bit length is selected.
Stop Bit
One bit or more are required for the stop bits. However, when DIP switch 1-3 is ON
and is set to 7 bits, and when there is no parity setting by SW 1-6 and SW 1-7, there
is a need for 2 or more stop bits.
Parity
Whether a parity bit is to be used, and whether odd or even parity is to be used
is selected by SW 1-6 and SW 1-7. If a parity error is generated during the input
of data, whether the data is ignored or a “*” is to be printed, is selected by SW
1-8. If ON, the data is ignored. If OFF, the
“*”
mark is printed.
No parity
Odd parity
Even parity
SW1 -6 SW1-7
OFF OFF
ON ON
OFF ON
ON OFF
Note: All DIP switch selections should be performed with the power OFF.
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