OSDP Reader Installation Guide

Proper wiring and configuration process for OSDP Readers

Overview

Alloy Access supports OSDP readers, providing secure access control solutions. This guide will walk through the proper wiring and configuration process to ensure reliable operation in the field.

Required Materials

Before beginning the installation, verify the following components:

• Each reader requires a 120 ohm 1% ¼Watt end-of-line resistor.

• Your wiring should include 18AWG for power and 22AWG 2-wire RS485 compliant twisted pair shielded cable with drain wire (120 ohm characteristic impedance) for the reader connections.

Basic Installation Guidelines

We recommend establishing an earth-ground connection to the metal chassis. This allows you to utilize the two "Earth" terminals for connecting drain wires from each reader cable. The proper grounding ensures optimal performance and helps prevent communication issues.

Single Reader Installation

Installing a single reader is straightforward. Place a 120 ohm resistor across the RS485A and RS485B terminals closest to the reader. The AAC-2001 controller includes an internal end-of-line resistor, which should remain enabled for single reader installations (leave the TD terminals open).

Dual Reader Installation

When installing two readers, there are a few key differences to note. You'll need to place 120 ohm resistors at both readers, and importantly, you must connect a jumper wire across the TD terminals to disable the controller's internal EOL resistor. During the initial setup in Alloy Access, power up and configure one reader at a time to ensure proper addressing.

OSDP Video

Reader Addressing

Readers can be addressed using either configuration cards or through the Alloy Access software. For Wavelynx Ethos readers, simply power cycle the reader and present the appropriate configuration card within one minute of reboot. When using the software method, connect one reader at a time, navigate to the OSDP tab in Alloy Access, and click "Scan." After the reader is discovered (this may take up to a minute), you can edit its address as needed.

Important Installation Notes

Remember not to connect the drain wire from the reader pigtail to the cable drain wire when installing Ethos readers. For dual reader setups, verify that the TD terminals are properly jumpered and that 120 ohm resistors are correctly placed at each end of the RS485 bus. Take your time during the reader discovery process, as it may require up to a minute to complete.

Troubleshooting Tips

If you encounter communication issues, first verify your resistor placements and TD jumper configuration. For dual reader installations, confirm that you've addressed each reader individually and that the TD terminals are properly jumped. Always check your ground connections and ensure proper cable types are used throughout the installation.

This guide provides essential information for successful OSDP reader installation. For additional support or specific configuration details, please reach out to Alloy Access Support.