Two Reader Expansion Module (ADC-ACX2) - Data Sheet
Alarm.com’s Smarter Access Control is an ideal solution for any small or medium-sized business. The Two Reader Expansion Module is designed to add two extra readers to an Alarm.com Door Controller. Each ADC-ACX2 adds two reader ports, six relay outputs, and eight programmable inputs to the system. Connect the expansion module to the controller using a shielded, RS-485 twisted pair.
For larger commercial installations, Single and Two Reader Expansion Modules can be daisy-chained together.

Features
- Provides all I/O needed for two doors each using one reader
- Eight programmable inputs
- Two reader inputs
- Six relay outputs
- For use with Alarm.com Door Controllers
Smarter Access Control benefits
- Scan-to-add card format and serial detection
- Control doors and manage users from the Alarm.com Alarm.com app
- Integrated Alarm.com intrusion and video offerings
- User-friendly, flexible scheduling
- Configure hardware using web or app for easy installation
- Plug & play installation — no networking expertise required
Specifications
| Input Power |
12/24V DC, 550mA max, 450mA nominal @ 12V 270mA nominal @ 24V |
|---|---|
| Output Power | 12V DC, 125mA per reader |
| Communication | 2-Wire RS-485 |
| Inputs |
Two dedicated reader inputs Eight programmable inputs One dedicated tamper input One dedicated power monitor input |
| Outputs |
Six relay outputs (5A @ 28V DC) Single-wire LED control Single-wire buzzer output |
| Certifications |
UL 294 recognized CE compliant ROHS |
| Dimensions | 6.0 x 8.0 x 1.0” (152 x 203 x 25 mm) |
| Temperature |
-40 – 167°F (-40 – 75°C) operational -67 – 185°F (-55 – 85°C) storage |
| Operating Humidity | 0-95% (non-condensing) RH |

Developed with the Authentic Mercury open hardware platform