Datasheet

Page 1-12 S400/S600 Maintenance Manual 44895L Rev. 3 3/12/04

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RS-232 Transmit and Receive Data

RS-232 data signals are defined as either MARK or SPACE while control signals are

either On (active—positive voltage) or Off (inactive—negative voltage). Although the

permitted voltage levels can range from 3 VDC to 25 VDC, both positive and negative, the

levels for the S400 and S600 printers are shown in Figure 1-4.

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The S400 and S600 printers have a standard 36-pin Centronics parallel connector

(instead of a serial port) available at the rear of the printer, for connection to a parallel

data source. This data communication method sends the bits of data that make up each

character all at one time over several wires in the cable, one bit per wire.

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Table 1-9 on page 1-13 shows the pin configuration and function of a standard PC-to-

printer Centronics parallel cable.

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Parallel data signals are defined as either HIGH or LOW, while control signals are either

active or inactive, meaning that some control signals are active HIGH while others are

active LOW. The voltage levels that represent these conditions are:

Figure 1-4. RS-232 Signal/ASCII Code Data

Data Signal Voltage Level

HIGH +5 VDC

LOW 0 VDC

Logic 0

Logic 1

(Idle)

– Mark

+ Space

Start

Bit

Data Bits

Parity

Bit

Stop

Bit

(Idle)