Epson LQ-1050 User Manual page 129

Pin labels
To tell the printer which pins to fire in each column, you first divide
each of the vertical columns into three sections of eight pins each
and consider each section separately. Since there are 256 possible
combinations of the eight pins in each section, you need a
numbering system that allows you to use a single number to specify
which of the 256 possible patterns you want. This numbering
system is shown below:
To fire any one pin, you send its number to the printer. To fire more
than one pin at the same time, add up the numbers of the pins and
send the total. Using these labels for the pins, you fire the top pin by
sending 128. To fire the bottom pin, you send 1. If you want to fire
only the top and bottom pins, you simply add 128 and 1, and send
129.
By adding the appropriate label numbers together, you can fire any
combination of pins. Below are three examples of how to calculate
the number that will fire a particular pattern of pins.
128
64
32
16
8
4
2
1
Software and Graphics
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