User Manual

Connecting Peripheral Devices
April 2008 Revision 2.2 35/41
7 Connecting Peripheral Devices
7.1 Using the Universal Input pin
The reader input can be driven by a voltage source from 0V up to 25V referring to the input ground.
A relay (open chain transistor, switch…) can also be used to connect the input pin and its ground.
- Low level input voltage is defined to be in the range of 0 to 1.5V
- High level input voltage is defined to be in the range of 3 to 25V
7.2 Using the Universal Output pin
The output pin is an open drain power transistor that can drive a current up to 6A. When activated,
the power transistor connects the output pin and its ground.
The output transistor is protected against heating and current overload. If an overload happens, the
output stops driving current automatically. The output must be turned off to be re-activated.
7.2.1 Output Wiring
Example: Connecting a LED to the Output
+12V (Input voltage)
Pin 1
Pin 2
470 Ohms
The LED’s cathode is connected to the
Output pin and its anode to the Output Supply
Pin. Note that the Output supply selector is
configured to deliver 5V to supply the LED.
The internal serial resistor limits the current
delivered to the LED.