Access control and time attendance
An access control system answers two questions: who may come in and who was here when. The first is security, the second is time attendance — and both come from the same events. No separate clock-card system is needed.
1. What the system is made of
| Part | Role |
|---|---|
ASI | Controller and reader in one device. The simplest route: one unit beside the door, deciding for itself. Suits one or two doors. |
ASC | A separate controller, usually on a DIN rail in a cabinet (for example four doors over TCP/IP). Readers sit at the door while the decision-making and wiring stay in the cabinet — safer and easier to maintain. |
ASR | Reader at the door: card, PIN keypad, fingerprint. IP55/IP67 models for outdoors. |
ASM | USB desktop reader for the office — for enrolling cards and fingerprints without standing at the door. |
Which one: for one or two doors that will not grow,
ASI is quickest and cheapest. When doors are added, when central user management is
needed, or when the reader sits somewhere a person could unscrew it, choose ASC +
ASR. Putting the controller in a cabinet means that opening the reader does not
open the door.2. How a person is identified
| Method | Strength | Weakness |
|---|---|---|
| Card / fob | Cheap, fast, easy to issue and revoke. | Can be passed on or lost. |
| PIN code | Nothing to carry. | Codes get shared; keypads wear and reveal the frequently used keys. |
| Fingerprint | Tied to the person, cannot be handed over. | Awkward where hands are dirty or wet. |
| Face recognition | Contactless and fast, good for high traffic. | More expensive; personal data handling needs thought. |
Card technology matters. Our range covers both
Mifare 13.56 MHz and the older EM 125 kHz. For a new site
choose Mifare — it is more secure. If cards are already in use in the building, check which type
they are before ordering: a reader on the wrong frequency will not read them at all.
In practice a combination works best: a card for everyday
use, and a PIN or fingerprint where you need certainty that it was that particular person — a
server room or a stockroom, for example.
3. Time attendance
Every access event is a record: who, which door, what time, in or out. Time attendance is a summary of those records — no extra hardware, just software that turns events into a report.
- Decide which readers count as attendance. Usually the main entrance; internal doors stay access-only.
- Link cards to people. A card carries a name, not just a number.
- Define working hours and shifts. That lets the system separate lateness from overtime.
- Take the report. Export at month end for payroll.
On the software side, a smaller site is covered by
Smart PSS Lite, which handles access control and time attendance as well as
video. For a larger system or several sites, DSS is the right place. See the
software page.
Two things to settle from the start.
1. Fire safety and evacuation. Access control must never prevent people leaving. An escape route door has to open during a power failure and an alarm — that is solved with the lock type and the fire system interface, not with a software setting.
2. Personal data. Time attendance is processing of employee personal data, and a fingerprint is a special category of data. Before going live it must be clear what is collected, how long it is kept and who can see it.
1. Fire safety and evacuation. Access control must never prevent people leaving. An escape route door has to open during a power failure and an alarm — that is solved with the lock type and the fire system interface, not with a software setting.
2. Personal data. Time attendance is processing of employee personal data, and a fingerprint is a special category of data. Before going live it must be clear what is collected, how long it is kept and who can see it.
Compiled from the Videovalve range and Dahua product documentation. Door capacities, reader compatibility and interfaces (Wiegand, RS485) are on the product datasheet.