OSDP™

OSDP™ is an industry standard for communication between card readers and control panels, which is maintained by SIA - the Security Industry Association.

In 2020 the OSDP standard became part of the international IEC set of industrial standards as EN IEC 60839-11-5:2020.
OSDP™ is designed to replace legacy card reader interfaces like Wiegand, Clock/Data and current loop.

The OSDP™ protocol allows for secured two-way communication between card reader and control panel over a standard two-wire RS485 multi-drop bus. The control panel function as the OSDP™ master device which communicates with one or more card readers on the same bus.
A legacy Wiegand interface requires 6 to 8 wires to function, but the OSDP™ interface only needs 4 wires to allow for data exchanged between card reader and control panel.
The security function in the OSDP™ protocol allow for multiple encryption standards including 128 Bit AES.

The OSDP™ protocol describes one or more of the following functionalities in a device:
   • Device status (Tamper & Power monitor, Status indication visual and/or audible)
   • Card Reader
   • PIN pad
   • Text display
   • Biometrics

The following functions are the basic functionality in OSDP protocol:
   • Capability data – Peripheral Devices (PD) -> Control Panel (CP)
   • Event data – Peripheral Devices (PD) -> Control Panel (CP)
   • Status Data – Control Panel -> Peripheral Devices
   • Text Data – Control Panel -> Peripheral Devices
   • Configuration – Control Panel -> Peripheral Devices