RS-232↔485/422 CONVERTERS
Figure 7 shows a typical multipoint, 4-wire, full- or half-duplex connection. Figure 8 shows a typical multipoint, 2-wire, half-duplex connection. In the multipoint applications depicted in Figures 7 and 8, the devices at the extreme opposite ends of the installation are terminated by setting switch S2 to the TERM position. These devices are the two devices that have the greatest cable length between them, not necessarily the devices that are physically located the farthest apart. (See Figures 7 and 8.) A resistor shown in the circuit indicates that the termination resistor has been selected via switch S2. Note that although Figures 7 and 8 show only four RS-232↔485/ 422 Converter devices networked together, up to 64 units can be connected in the manner shown in Figure 7, and up to 32 units as shown in Figure 8.
Figure 7. Multipoint, 4-Wire (Half- or Full-Duplex).
24
