OSDPv2 RS485 Expansion Module

Secure access control with OSDPv2 encryption directly in the monitoring system

The Didactum OSDPv2 RS485 expansion module is a key component for modern access control and security monitoring in businesses. As an expansion board, it is installed directly into a compatible Didactum monitoring system (100T, 300T, 500T, or 550T) and enables the connection of OSDP-compatible card readers, keypads, and biometric devices via a secure RS-485 connection. This makes it possible to precisely control who is granted access to a protected area, when, and how.

By integrating it into the Didactum monitoring system, access events can be linked directly with other environmental parameters such as temperature, humidity, smoke, or water ingress. In the event of suspicious activity, such as an unauthorized access attempt outside business hours, the system can automatically trigger an alarm, lock doors, or notify security personnel. OSDPv2 secure channel encryption prevents unauthorized parties from manipulating or eavesdropping on communication between the reader and the control center.

Thanks to OSDPv2's bidirectional communication, status messages and diagnostic data from connected readers and keypads can also be transmitted back to the monitoring system, allowing maintenance needs, tampering attempts, or technical faults to be detected at an early stage. Central administration and configuration of all access devices is conveniently handled via the web interface of the respective Didactum monitoring system.

Typical use cases for the expansion module

Wherever physical access to sensitive areas must be protected and documented without gaps, the OSDPv2 RS485 expansion module demonstrates its strengths.

Main features of the OSDPv2 RS485 expansion module

Compact expansion board with a modern security protocol for direct integration into Didactum monitoring systems.

OSDPv2 encryption as a security standard

OSDPv2 (Open Supervised Device Protocol) is an open, vendor-independent communication standard for access control components, designed specifically to address the weaknesses of older Wiegand wiring. Secure channel encryption prevents unauthorized parties from eavesdropping on, recording, or manipulating communication between the card reader and control center, a real security risk in unencrypted systems. In addition, the protocol continuously monitors the connection for tampering attempts and immediately reports faults or sabotage to the Didactum monitoring system.

Supported devices

The expansion module is designed for connecting a wide variety of OSDP-compatible access devices.

Setup in just a few steps

Installation is straightforward and can even be carried out while the monitoring system is running.

1. Insert the expansion board into the designated slot in the Didactum monitoring system — shutting down the system is not required.
2. Check internal termination: enabled by default; disable if needed for longer bus lines or multiple modules.
3. Connect OSDP readers, keypads, or biometric devices to the module via RS-485 wiring (4P4C).
4. Detect and configure the connected devices in the web interface of the Didactum monitoring system.
5. Define user rights, access profiles, and alerting rules individually in the web interface.

Performance data at a glance

Up to 4 OSDP readers can be connected per expansion module. If the readers are powered via the module's internal power supply, it is recommended to limit the setup to 2 readers to ensure stable voltage. If higher power demand or more connected readers are required, an external power supply for the readers should be provided.

What is included

Please check the delivery for completeness upon receipt and report any missing or damaged parts to your supplier immediately.

• OSDPv2 RS485 expansion module (board)1 piece

OSDP readers, keypads or biometric devices, as well as the required RS-485 cabling materials, are not included and must be purchased separately.

Why the OSDPv2 RS485 expansion module is the right choice

Practical application examples

• Access control and complete logging in the server room
• Management of different security zones in data centers
• Access restriction and documentation in research laboratories
• Protection of technical control centers against tampering and sabotage
• Flexible access control in office buildings including visitor management
• Linking access events with climate, smoke, and water monitoring
• Connection of smart card and biometric readers for the highest security requirements
• Automated alerts for unauthorized access attempts outside business hours

The Didactum OSDPv2 RS485 expansion module is the ideal solution for companies that demand the highest standards of security, flexibility, and future-proofing for their access control systems—from the server room to all critical business areas.

Frequently asked questions