
NT132 System Overview
18
750.001.003
Revised June 1999
© 1999 AXCESS
TM
Inc.
Antenna Tuning Unit (ATU)
An Antenna Tuning Unit or ATU (Figure 5) maximizes the signal
transmission from the Reader. It is installed between the Reader and
the transmitting and receiving antennas.
Figure 5 AXCESS ATU – external view
On the bottom of the ATU, there are two jacks to connect to the
transmitting and receiving antennas and two jacks to connect to the
Reader.
Types of ATUs
There are two kinds of ATUs currently provided. Although they
require different methods of optimizing performance, they perform
the same function.
Toggle Switch ATU
This ATU has a toggle switch, a rotary switch and a voltmeter. The
antenna performance is tuned by toggling one switch between three
positions and turning the other switch among ten positions. The
voltmeter indicates when the optimal setting has been reached.
Jumper ATU
This ATU has eleven 3-pin headers and five LEDs. The antenna
performance is tuned by moving jumpers on the headers. Optimal
performance is indicated by the strength of the LEDs.