On this page
01. How a door decides02. Credentials03. Locks and what happens without power04. Standalone vs networked05. See it in a real installation06. FAQ
An access control system decides who can open a door and when. A reader identifies the person (card, fingerprint, face or PIN), a controller checks whether they're allowed in right now, and if so it releases an electric lock. An exit device lets people out, and software records every event.
Key takeaways
- Five parts: reader, controller, lock, exit device, software.
- The controller makes the decision, not the reader.
- Fail-safe locks unlock when power is lost; fail-secure locks stay locked.
- Escape routes must always let people out.
- Every entry is logged, and lost credentials can be disabled instantly.
01How a door decides
- 01Present credentialCard, finger, face or PIN at the reader
- 02Controller checksIs this user allowed through this door at this time?
- 03Lock releasesFor a few seconds, then relocks
- 04Door sensor confirmsKnows the door opened and closed
- 05Event loggedWho, which door, when
02Credentials
| Credential | Strength | Weakness |
|---|---|---|
| Card / fob (RFID) | Cheap, fast, familiar | Can be lent, lost or copied (older types) |
| PIN | No hardware to carry | Codes get shared |
| Fingerprint | Can't be lent | Worn or wet fingers; reader placement matters |
| Face | Hands-free, fast | Lighting and privacy considerations |
| Mobile / QR | Great for visitors | Needs a phone and the right system |
Compare the biometric options in fingerprint vs face recognition.
03Locks and what happens without power
Fail-safe
Fail-secure
04Standalone vs networked
Standalone
Networked
Planning a system? Start with the access control planning guide.
05See it in a real installation
Face Recognition Access Control on an Office Door
A face recognition terminal, with a fingerprint sensor as a second option, mounted beside an office door. Authorised staff are recognised and the door releases.
Fingerprint Door Access Control: How It Works
A fingerprint and keypad access control reader mounted beside a glass office door. Staff unlock the door with a fingerprint, with a PIN as a backup.
06Frequently asked questions
What happens to access control in a power cut?
It depends on the lock. Fail-safe locks release; fail-secure locks stay locked. Backup batteries keep the system working through outages.
Can I get a report of who entered?
Yes. Every access event is logged and can be exported as a report.
What if an employee loses their card?
The card is disabled in the software straight away and a new one is issued. No locks need changing.
