Star Micronics 4111 manual Serial interface rate, Serial interface special bits

Most MS-DOS and AT-compatible computers support up to three parallel and two serial ports, which come on expansion boards you plug into your computer. When you install such boards you must set switches to indicate the number and addresses of these ports. If you specify the wrong addresses, you won’t be able to print.

Serial interface: rate

If you ask for the Serial interface you’ll have to tell your printer more about how the data will be coming in — in particular its rate and unit size and the meanings of any special bits.

The Rate parameter specifies how fast data will be arriving, measured in baud (named after the French communications engineer Jean Baudot). Pick any of the following data transfer rates:

300baud

600baud

1200 baud

2400 baud

4800 baud

9600 baud (the default)

19200 baud

38400 baud.

Roughly, one character a second works out to 11baud. If you’re not sure how fast your computer will transmit, the general rule is to experiment. Try sending a page to print at the highest speed, and work your way down until the printer’s output looks OK.

Serial interface: special bits

In Serial mode you’ll also have to specify if your computer sends data bits in groups of seven (most computers send eight, the default for a byte).

Sometimes an extra bit gets appended to make the sum of all bits in each character always odd or even; that’s called parity. A parity bit can help spot transmission errors. If your computer sends that extra parity bit, you’ll have to say whether it produces anevenorodd number of “on” bits in the character.

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