Security
OSDP vs Wiegand
Also called: OSDP, Wiegand protocol, SIA OSDP
Two reader-to-controller protocols. Wiegand is legacy, one-way, and unencrypted; OSDP is bidirectional, supports encryption, and reports reader tampering and health.
Wiegand's flaw is that credential data travels in the clear on the reader's cable, so a small device hidden behind a reader can capture and replay credentials. OSDP with Secure Channel encrypts that link and lets the controller see reader status, firmware, and tamper events instead of only receiving card numbers.
Because OSDP runs over a two-conductor RS-485 bus, it also simplifies wiring and supports longer runs and multi-drop. On any new install, OSDP is the default; on retrofits, converters buy time, but the reader cable is the part worth replacing when walls are already open.
Related terms
- Access Control
- A system that decides electronically who may open which door, when, and records every attempt — replacing mechanical keys with credentials and policy.
- Mobile Credential
- A door credential held in a phone's wallet or an app and presented over Bluetooth or NFC, replacing a plastic card or fob.
More Security terms
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