Lexmark Printer manual Serial Communication Parameters RS-232C, Voltage Level Range

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Interfaces

Serial Communication Parameters (RS-232C)

The following paragraphs show acceptable values for serial communication parameters.

Voltage Level Range

The maximum voltage level for control lines or data lines is +/- 25 positive V dc and +/- 25 negative V dc. A timing or control line is active if the voltage is more than +3 V, or inactive if the voltage is less than –3 V. The voltage reference point is the signal ground on pin 7.

A data signal greater than +3 V means that the bit is a logical 0. A signal less than –3 V means that the bit is logical 1.

For additional information, refer to Interface between Data Terminal Equipment and Data Communications Equipment Employing Serial Binary Data Interchange, published by the Electronic Industries Association, publications EIA RS-232C and EIA\TIA-232-E.

Serial Data Frame Considerations (RS-232C)

The computer sends serial data in data frames (also known as packets). You can create 10-bit, 11-bit, and 12-bit data frames and set the serial data transfer parameter so that each data frame contains 7 or 8 data bits. However, your printer is an 8-bit printer; characters, controls, and all points addressable (APA) graphics need 8 bits of data. If you select 7-bit data transfer, some unexpected characters might print.

Data Transmission

The list of acceptable data transfer rates (in bits per second) can be accessed from the printer operator panel or through MarkVision Professional. Refer to your printer user documentation for more information.

Data Bits

The printer sends or receives 7 or 8 data bits in each transmission frame, depending on which one is selected.