Wiegand and OSDP comparison guide

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For decades, the Wiegand interface served as the industry standard for Access Control wiring. However, the industry has shifted toward the Open Supervised Device Protocol (OSDP) to address the physical and digital security vulnerabilities inherent in those legacy systems.

Wiegand and OSDP comparison

Feature	Wiegand (Legacy)	OSDP (Recommended)
Conductors Required	6 Conductors This includes 6 conductors (i.e., Power, Ground, D0, D1, LED, and Buzzer).	4 Conductors This includes 4 conductors (ie., Power, Ground, Data A, and Data B) and uses shielded twisted pair 22 AWG.
Max Distance	~500 feet (150m) Gauge dependent and subject to voltage drop and interference.	1,000 feet (305m) Uses RS-485 signaling for long-range stability.
Communication	Unidirectional (One-way) The reader sends data; The panel cannot reply or check status.	Bidirectional (Two-way) The panel and reader constantly talk; The panel knows if the reader is offline.
Security	None Data can be easily sniffed or cloned. No encryption.	High Supports AES-128 encryption to prevent cloning and tampering.

Feature

Wiegand (Legacy)

OSDP (Recommended)

Conductors Required

6 Conductors

This includes 6 conductors (i.e., Power, Ground, D0, D1, LED, and Buzzer).

4 Conductors

This includes 4 conductors (ie., Power, Ground, Data A, and Data B) and uses shielded twisted pair 22 AWG.

Max Distance

~500 feet (150m)

Gauge dependent and subject to voltage drop and interference.

1,000 feet (305m)

Uses RS-485 signaling for long-range stability.

Communication

Unidirectional (One-way)

The reader sends data; The panel cannot reply or check status.

Bidirectional (Two-way)

The panel and reader constantly talk; The panel knows if the reader is offline.

Security

None

Data can be easily sniffed or cloned. No encryption.

High

Supports AES-128 encryption to prevent cloning and tampering.

For more information about Wiegand reader wiring, see Wire a Wiegand reader or keypad to a door controller or expansion module.

For more information about OSDP reader wiring, see Wire and configure an Alarm.com brand reader or keypad for OSDP to a door controller or expansion module.

OSDP supported features

The following features are enabled when using OSDP mode.

Secure channel encryption: Prevents man-in-the-middle attacks and wire tapping.
Device monitoring: Instant alerts if a reader goes offline or is tampered with.
- For more information, see Access Control tampers.

Reader modes outside of Badge or Pin (i.e., Badge Only, Pin Only, or Badge and PIN)
Dual Access Mode
- For more information, see Dual-Access Mode.
  
  Note: Dual Access Mode requires the Smarter Access Control Plus service package.