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Rs-485 programming, Addc(tm) (automatic data direction control), Rs-485 programming -5 – Moxa Technologies CP-132U Series User Manual

Page 71: Addc™ (automatic data direction control)

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Software Installation

CP-132U Series User’s Manual 4-5

RS-485 Programming

If you intend to use your CP-132UL Series board for RS-485 applications, you can refer to
the RS-485 programming guide below, and also see the chapter, “Connection Cables and
Cable Wiring,” for more details about RS-485 operation.

The CP-132UL Series supports only 2-wire half-duplex RS-485 communication. In this
case, the data+/- pins are used for both data transmitting and receiving, depending on the
mode selected. The modes available are ADDC™ (Automatic Data Direction Control), or
By RTS.

ADDC™ (Automatic Data Direction Control)

The ADDC™ scheme is the best solution for RS-485 applications. To use ADDC™ mode,
set the mode switch to the ON position.

Under this mode, no extra code is required to control data transfer (both data transmitting