Revision A
6/21/2019
tres900s Operations Manual
Page
5
LED Control
This is an LED control output; it will power an LED with 3.3v DC. The LED+ goes to the
Anode of the LED while the LED- goes to the Cathode of the LED.
RS232 Control
This input / output lines are used to control or be controlled by and RS232 device. Line
description, 232T goes to pin 3 of a 9-pin DIN (RX), 232R goes to pin 2 of a 9-pin DIN (TX)
and 232- goes to pin 5 of a 9-pin DIN (ground).
RS485 Control
This input / output lines are used to control or be controlled by and RS485 device. Line
description, 485B normally goes to the T/R- or 485B line, 485A normally goes to the T/R+ or
485A line and the 485- is the Ground line.
Earth
Here you would connect an Earth ground to the reader instead of or still to the back panel of
the reader.
Power Connect
This is where you get power to the reader from TRES supplied regulated power supply.
Remember to use the TRES regulated DC 5vDC @ 2A. The reader has a built-in linear
regulator with EMI, reverse polarity and overvoltage protection.
