With older Wiegand credential readers, each controller input was limited to a single reader without any issues. However, OSDP readers support Multi-Drop functionality, allowing up to two OSDP readers to connect to a single OSDP-enabled port. Having multiple readers reduces the number of door nodes, making it ideal for setups that require two readers at one door.
Note: Multi-drop readers share a single relay, making them best suited for IN-OUT reader configurations at a door.
Mercury access controllers support OSDP multi-drop, enabling multiple readers to communicate over a single RS-485 bus. This simplifies wiring while ensuring secure, encrypted communication using AES-128 encryption. Each reader is assigned a unique OSDP address, allowing seamless integration of entry and exit readers.
Mercury’s LP, EP, and MP series controllers fully support OSDP multi-drop, enhancing scalability, real-time device supervision, and security. This setup is ideal for high-security doors, shared entry points, and advanced authentication scenarios, making access control more efficient and cost-effective.
See table below for list of supported hardware and reader configurations.
Controller Model Number | Onboard reader ports | Max onboard OSDP readers per controller |
LP1501 | 2 | 2 (two on one port only) |
LP1502 | 2 | 4 (two per port) |
LP4502 | 2 | 4 (two per port) |
MR52 (Series 3) | 2 | 4 (two per port) |
MR50 (Series 3) | 1 | 2 (two on one port) |
MR51e | 2 | 2 (two on one port only) |
MR62e | 1 | 4 (four on one port) |
EP1501 | 2 | 2 (two on one port only) |
EP1502 | 2 | 2 (one per port) |
EP4502 | 2 | 2 (one per port) |
MP1501 | 2 | 2 (two on one port only) |
MP1502 | 2 | 4 (two per port) |
MP4502 | 2 | 4 (two per port) |
In this article, you'll find a detailed guide on setting up and configuring OSDP multi-drop with HID and Wavelynx readers communicating with Mercury controllers. Keep reading.
OSDP Multi-Drop Reader Wiring:
HID Reader
Wavelynx Reader
RS485A+ (Green wire) | CLK (Clock Line) / D1 |
RS485B- (White wire) | DAT (Data Line) / D0 |
Power (Red wire) | Power In |
Ground (Black wire) | Ground |
Shield (Shield Ground wire) | Shield Ground |
Other optional wires:
Yellow → Beeper Control
Brown → Tamper Out
Blue → Green LED Control
Orange → Red LED Control
For Multi-Drop, follow the same wiring for the second reader on the same reader port.
Addressing the Readers:
Each Mercury interface can support up to four readers, with each reader requiring a unique address. Using a mobile device, you can assign addresses 0, 1, 2, and 3 to the OSDP readers via the HID Reader Manager or Wavelynx Mobile application (if using a Wavelynx reader).
Reader Port 1 will use Readers 0 and 2.
Reader Port 2 will use Readers 1 and 3.
This ensures proper communication and seamless integration of multiple readers within the Mercury interface.
Configure OSDP Multi-Drop Reader from HID Reader Manager App:
Configuring an OSDP reader for multi-drop requires setting the baud rate, assigning a unique address, and turning off auto-discover mode.
Please follow the steps outlined here for the setup.
Configure OSDP Multi-Drop from Wavelynx Mobile App:
Refer to this article for configuring Wavelynx Reader.
Configure OSDP Multi-Drop Readers in Genea
1. Go to the Hardware section in the Genea admin dashboard and select Doors.
Add a new door by entering a name and description.
2. Next, add the first OSDP reader by selecting the reader model number, setting the reader type to "Paired Reader - Primary," and choosing the controller. Then, select the reader port and assign the reader address. Fill in the remaining details and click Save to add the reader.
3. To add a second OSDP reader to the same reader port, start by adding another door. When attaching the door, select "Paired Reader - Secondary" as the reader type and choose the primary reader. Complete the remaining details and click Save.
4. Once saved, the OSDP readers will operate the same relay and share the same port on the controller.
If you have any questions about this feature or have any other requests, please reach out to acsupport@getgenea.com.