PRELIMINARY TECHNICAL DATA
ADM1486
RT
D
R
R
D
RT
D
R
R
D
Figure 11. Typical RS-485 Network
Table III. Comparison of RS-422 and RS-485 Interface Standards
Specification
RS-422
Transmission Type
Differential
Maximum Cable Length
4000 ft.
Minimum Driver Output Voltage ±2 V
Driver Load Impedance
100⍀
Receiver Input Resistance
4 k⍀ min
Receiver Input Sensitivity
±200 mV
Receiver Input Voltage Range –7 V to +7 V
No of Drivers/Receivers Per Line 1/10
RS-485
Differential
4000 ft.
±1.5 V
54⍀
12 k⍀ min
±200 mV
–7 V to +12 V
32/32
PROFIBUS
Differential
-
±2.1 V
54⍀
200 k⍀ min
±200 mV
–7 V to +12 V
50/50
REV. PrB
–5–