Lesson 3.1: Wiegand vs. OSDP
Lesson 3.1: Wiegand vs. OSDP
⚡ The Logic (Mermaid)
graph TD
subgraph Legacy [Wiegand - Unsecure]
W_READ[Wiegand Reader] -- D0, D1, LED, BZ (5-7 Wires) --> W_CTRL[Legacy Controller]
W_CTRL -.->|No Feedback| W_READ
end
subgraph Modern [OSDP - Secure]
O_READ[OSDP Reader] -- RS-485 A/B (2 Wires + Power) --> O_CTRL[Inner Range Controller]
O_CTRL <-->|AES-128 Encryption| O_READ
O_CTRL -- Query Status --> O_READ
end Hardware Landmark: OSDP RS-485 Wiring
!400
Above: A modern OSDP reader terminal block. Note it only requires 4 wires total: +12V, GND, and the RS-485 pair (A and B).
🧠 The Concept
Wiegand is a 40-year-old protocol that sends data in the clear—it can be easily sniffed. OSDP (Open Supervised Device Protocol) uses RS-485 and AES-128 encryption. Inner Range Integriti and Inception both support OSDP natively, allowing the controller to "talk back" to the reader and monitor its health.
🛠️ Hands-on Steps
- The Pair: Use a twisted-pair cable (like Cat6) for the A and B lines to prevent interference.
- Addressing: Unlike Wiegand, OSDP readers need an address (usually Address 0 or 1). This is set via DIP switches or a configuration card.
- Termination: If the reader is at the end of a long cable run (>100m), ensure the 120-ohm termination resistor is engaged.
- Encryption: In the Inner Range software, "Install" the reader and enable "Secure Mode" to activate AES encryption.