ib technology

23

In this manner the user can select to use the UID (serial number) or user programmed

information within a memory block as the base data for the Wiegand output. The complete

data frame is output whenever the tag is within the RWD’s antenna field and the tag has been

validated. This output is independent of the normal TTL serial interface which responds to

received commands and replies with the data as requested.

The physical Wiegand protocol is asynchronously transmitted as low going 50 µS pulses on

the appropriate DATA low or DATA high pins. These pulses are separated by 2mS periods.

The Wiegand sequence is output a single time whenever a valid tag enters the RF field for the

first time. (NO Wiegand output if AUX OUTPUT parameter is ZERO/OFF).

Wiegand Protocol Timing Diagram

TTL level

5v

0v

5v

0v

DATA High

DATA Low

50 µS pulse

2mS pulse intervals

DATA

1

0

1

0