ADM2482E/ADM2487E
Rev. A | Page 17 of 20
07
37
9-
02
7
NOTES
1. RT IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE.
2. ISOLATION NOT SHOWN.
TYPICAL APPLICATIONS
ADM2482E/ADM2487E in half-duplex and full-duplex
RS-485 network configurations. Up to 256 transceivers can
be connected to the RS-485 bus. To minimize reflections, the
line must be terminated at the receiving end in its characteristic
impedance, and stub lengths off the main line must be kept as
short as possible. For a half-duplex operation, this means that
both ends of the line must be terminated, because either end can
be the receiving end.
AB
Z
Y
AB
Z
Y
A
B
Z
Y
A
B
Z
Y
R
D
R
D
R
D
R
D
ADM2482E/
ADM2487E
ADM2482E/
ADM2487E
ADM2482E/
ADM2487E
RxD RE
DE TxD
RxD RE
DE TxD
RT
RxD
RE
DE
TxD
RxD
RE
DE
TxD
ADM2482E/
ADM2487E
MAXIMUM NUMBER OF TRANSCEIVERS ON BUS = 256
NOTES
1. RT IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE.
Figure 35. ADM2482E/ADM2487E Typical Half-Duplex RS-485 Network
R
D
A
B
Z
Y
R
D
A
B
Z
Y
R
D
A
B
Z
Y
R
D
A
B
Z
Y
RT
TxD
DE
RxD
RE
ADM2482E/
ADM2487E
ADM2482E/
ADM2487E
ADM2482E/
ADM2487E
SLAVE
RxD
RE
DE
TxD
ADM2482E/
ADM2487E
MASTER
SLAVE
RxD RE DE TxD
RT
07
37
9-
0
28
MAXIMUM NUMBER OF NODES = 256
Figure 36. ADM2482E/ADM2487E Typical Full-Duplex RS-485 Network