National Instruments 321827C-01, PCMCIA Serial Hardware and Software for Windows Me/9x Half Duplex

Appendix A Serial Port Information
PCMCIA Serial for Windows Me/9x A-4 ni.com
Figure A-1. Typical Full-Duplex System
Half Duplex
A typical half-duplex multidrop bus architecture also involves a
master-slave protocol. However, in a half-duplex system, all transmitters
and receivers are connected to the same transmission line. A half-duplex
system is often referred to as a two-wire system. FigureA-2 shows a typical
half-duplex system.
Figure A-2. Typical Half-Duplex System
MASTER
Slave 1 Slave 2 Slave n
Tx
Tx Rx Tx Rx Tx Rx
Rx
MASTER
Slave 1 Slave 2 Slave n
Tx
Tx Rx Rx Tx Rx Tx
Rx