Lexmark Printer manual Serial Communication Parameters RS-422, Voltage Level

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Interfaces

Serial Communication Parameters (RS-422)

The following paragraphs show acceptable values for serial communication parameters.

Voltage Level

RS-422 serial interface uses a differential pair, 5-volt typical delta, 0.5 volt threshold. Your printer uses a TI75179 transceiver with transorbs. The polarity of the signals is programmable.

Serial Data Frame Considerations

The computer sends serial data in data frames (also known as packets). You can create 10-bit, 11-bit, or 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 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 your printer operator panel or through MarkVision Professional. Refer to your printer user documentation for more information.

Data Bits

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

Start and Stop Bits

Your printer receives data with 1 start bit and either 1 or 2 stop bits. The printer always sends 1 start and 2 stop bits.