User's Manual

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5 Description of hardware near functions
5.1 Cold start
After a cold start the system is initialized using the parameter values out of the EEPROM. The indica-
ting elements (relays / LEDs) are cleared.
5.2 Interface to the master
The serial interface permits communication between the reader and a master (e.g. terminal or PC). The ba-
sic configuration of the interface is 19200baud and 8N1 (8 bit, no parity and 1 stop bit). With the com-
mand BD the reader can be set to a different baud rate. Changing the data format (8 data bits, no parity, 1
start- and stop bit) is not possible. The same applies to hardware-handshaking, e.g. Xon/Xoff or RTS/CTS.
5.3 Digital trigger input
For the operating mode 1 - externally triggered - a digital input channel is required. The following logical
function is defined:
5.3.1 Logical level
If the digital input is open (not connected), then it is in the logical state zero (0). By feeding the defined
input voltage the digital input has one-level (1).
5.3.2 Timing characteristics
When triggered externally, the first reading process is initiated by a change from 0 to 1 (leading edge) -
see chapter 2.3.
5.4 Digital trigger outputs
Two specified digital outputs are defined as follows: