What is 'Multi-drop' when using OSDP readers?

What is 'Multi-drop' when using OSDP readers?

With older Wiegand credential readers, a reader input connection on a controller was limited to a single reader being used without issues. With OSDP readers, the 'Multi-Drop' function allows you to connect up to four (4) readers to a single OSDP-enabled port or controller.

How do I wire and configure an OSDP reader for 'multi-drop'?

Wiring an OSDP reader is a little different compared to older Wiegand readers. This is complicated even further when using the 'Multi-Drop' function of OSDP. With older Wiegand wiring, each reader is individually wired back to the controller, while OSDP readers allow an installer to daisy-chain the multiple OSDP readers to the controller. With daisy-chain-connected readers, an installer must place the OSDP jumper for the reader port on the PDK controller board. The installer will also need to take note of the serial number on the Red Reader so that you can confirm which reader is being configured.

Below we will outline how to multiple OSDP readers to a single controller port.

Daisy-Chain Connection:

1. Connect the wiring from the reader port on the Red controller to the first OSDP reader.
2. Add the first reader to the PDK system. 
   Put a checkmark in the OSDP box and then click on the gear next to OSDP.
   Set the OSDP Address to a value other than the default of 0.
3. Connect the wiring for the second reader to the wiring connectors on the first OSDP reader.
4. Add the second reader to the PDK system. 
   Put a checkmark in the OSDP box and then click on the gear next to OSDP.
   Set the OSDP Address to a value other than the previously added reader.
5. Repeat the process above for each additional reader (to a maximum of four) to the previously installed reader and add the readers to the PDK system.