Industry standard · Cypress resource center
What is OSDP?
Open Supervised Device Protocol is the secure, two-way communications standard connecting access-control readers and controllers. Explore the standard, its benefits, migration guidance, videos, FAQs, and industry updates in one place.
Secure supervised bus
ACU
01
02
03
AES-128 secure channel
Two-way
Supervised
Multi-drop RS-485
The standard at a glance
A safer connection at the door.
OSDP is a command-response protocol owned and maintained by the Security Industry Association. It runs over RS-485 between an access control unit and peripheral devices such as credential readers.
Unlike the one-way Wiegand interface, OSDP supports supervision, remote configuration, richer device commands, and Secure Channel encryption. It became the IEC 60839-11-5 international standard in 2020.
AES-128
Secure Channel encryption
2-way
Command-response communication
4,000 ft
Maximum RS-485 distance in appropriate designs
IEC
60839-11-5 international standard
Why the industry moved forward
Four advantages built into the protocol.
OSDP improves the security, visibility, flexibility, and long-term serviceability of access-control systems.
01
Security
Secure Channel adds AES-128 encryption and authentication between the reader and controller.
02
Supervision
Two-way communication lets the controller detect loss of power, vandalism, or a missing device.
03
Interoperability
OSDP Verified devices are independently tested against the standard and published profiles.
04
Functionality
Remote updates, richer device commands, larger credentials, and multi-drop topologies support more capable systems.
OSDP vs. Wiegand
The practical difference.
Wiegand established a common interface. OSDP adds the security and operational capabilities modern systems require.
Capability
OSDP
Wiegand
Communication
Two-way command and response
One-way reader output
Encryption
AES-128 Secure Channel
Not included
Supervision
Continuous device monitoring
Not included
Topology
Multi-drop RS-485 supported
Home run per reader
Maintenance
Remote configuration and file transfer
Physical service at the reader
From first lab test to full deployment
Choose the right adoption path.
OSDP can be introduced in phases. Start where risk is highest, validate the devices together, and expand with a documented key and wiring plan.
Retrofit
Bridge a legacy panel
Use an OSDP-to-Wiegand interface at the panel to secure the field connection while planning a later controller upgrade.
New installation
Design for OSDP from day one
Select OSDP Verified devices, suitable RS-485 cable, unique device addresses, and a secure key-loading process.
Lab and commissioning
Test before the field
Confirm addressing, baud rate, Secure Channel keys, cabling, and interoperability before deploying across the site.
Watch and learn
OSDP in the field.
A growing library for installation, retrofit, testing, and standards education.
How to retrofit Wiegand with OSDP
A practical walkthrough of retrofit strategy and the OSDP tools used to commission and troubleshoot a system.
Why OSDP?
An industry overview of secure, supervised, two-way communication and why integrators are moving beyond Wiegand.
Frequently asked questions
Start with the questions people ask most.
These answers come from the dedicated FAQ library, so updates made there flow into this hub automatically.
OSDP Overview
0 questions
OSDP Security
0 questions
OSDP Benefits
0 questions
OSDP Installation
0 questions
News, events, and industry reading
Follow the standard as it evolves.
The latest Cypress and industry items tagged OSDP are collected here automatically.
OSDP Integration Webinar
Join Cypress engineers for an educational webinar covering OSDP deployment best practices and common installation scenarios.
Read the storyCypress Announces Enhanced OSDP Support for the SPX-1300 Reader Extender
The latest SPX-1300 update expands OSDP compatibility and simplifies integration with modern access control systems.
Read the storyIML Security Expo Denver
June 23-25, 2026Denver, Colorado Join us at the IML Security Expo in Denver on June 25, 2026 to see time-saving access control accessories. (Industry courses also offered at the event on June 23 and 24). Learn about our OSDP cable test tool and OSDP Test &…
Read the storyNew Technical Resource Available: Understanding OSDP Deployment Best Practices
A new technical guide explains best practices for deploying OSDP in secure access control environments.
Read the storyCypress offers new OSDP Tool Kit to ensure OSDP systems are ready to deploy
LAPEER, MICHIGAN — Cypress Integration Solutions of Lapeer, Michigan, has introduced a new OSDP Tool Kit to ensure OSDP systems are ready to roll out before rolling trucks to customer sites. The OSDP Tool Kit (OTT-KIT1) is essential for anyone designing and…
Read the storyCypress Wireless Reader Extender now supports OSDP, Wiegand, and OSDP-Wiegand Systems
LAPEER, MICHIGAN — Cypress Integration Solutions of Lapeer, Michigan, has announced that its Suprex® Wireless Extenders now support OSDP. The updated Wireless Extenders support OSDP readers connected to OSDP controllers, Wiegand readers connected to Wiegand…
Read the storyPlanning an OSDP deployment?
Build the next connection on OSDP.
Explore Cypress OSDP tools, converters, splitters, and interfaces—or talk with technical support about commissioning and retrofit questions.
Designed, manufactured, and supported from Lapeer, Michigan.
