Technical specifications 
  5.2 HSPA+ router SCALANCE M874-3 
SCALANCE M874, M876 
Operating Instructions, 06/2015, C79000-G8976-C331-05 
53 
Power supply 
Terminal block, 5 terminals 
Properties  Input voltage: 
•  12 to 24 VDC 
•  min. 10.8 VDC, max. 28.8 VDC 
Maximum power consumption 8 W 
Maximum cable length < 3 m 
Digital input 
Terminal block, 2 terminals 
Properties  Rated voltage 24 VDC Safety Extra Low Voltage 
For state "1": 10 to 30 VDC 
For state "0": -30 to 3 VDC 
Maximum input current 8 mA 
Cables should be routed in pairs 
Maximum cable length < 30 m 
Inputs isolated from electronics. 
Digital output 
Terminal block, 2 terminals 
Properties  Rated voltage 24 VDC Safety Extra Low Voltage 
Relay, internally not current limited 
Maximum current carrying capacity 1 A 
Cables should be routed in pairs 
Maximum cable length < 30 m 
Output isolated from electronics 
Permitted ambient conditions 
  During transporta-
-40 ℃ to +70 ℃