User Manual

VEGACOM 557 Siemens 35
Supplement
Table: Comparison of important interface data
Interfaces RS 232 C RS 422 A RS 485
Transmission asym. symmetr. symmetr.
Number of drivers 1 1 32
Number of receivers 1 10 32
Transmission distance 15 m 1200 m 1200 m
max. transmission rate 20 KBit/s 10 MBit/s 10 MBit/s
Emitter
Permissible driver
output voltage ±25 V –0.25…6 V –7…12 V
Driver output signal
- without load ±15 V ± 5 V ± 5 V
- with load ± 5 V ± 2 V ±1.5 V
Driver load 3…7 kOhm 100 Ohm 54 Ohm
Receiver
Input voltage ±15 V ±7 V –7…12 V
Sensitivity ±3 V ±200 mV ±200 mV
Input resistance 3…7 kOhm 4 kOhm 12 kOhm
10km
1,2km
1km
100m
30m
15m
100 1k 10k 20k 100k
1M Bit/s 10M
RS 422-A
RS 485
RS 232-C
Distance
Transmission rate
Diagram: Distance –– Transmission rate