In previous articles, we discussed the difference between a reader and an all-in-one device in access control systems. Simplify, the reader is designed solely to capture credential data and must be connected with a controller. The reader transmits this data to the controller via RS485 or Wiegand protocols, after which the controller processes the access decision and triggers the door opening. But an all-in-one device integrates both the reader and controller functions into a single device. This means credential reading, access decision-making, and door control are all performed internally within the device itself—eliminating the need for an external controller.
In access control systems, whether standalone controllers or all-in-one devices—door unlocking is ultimately executed through a relay. QR code all-in-one machines also incorporate a built-in relay to enable direct door control. Given that a relay is already available for direct operation, one might wonder: why integrate Wiegand and RS485 interfaces? Is this redundant? In this article, we will explain the necessity of these interfaces from the following two perspectives.
The primary requirement for QR code access control all-in-one machines is to facilitate efficient management of visitors and temporary users. Traditional access control systems predominantly rely on card-based authentication for entry and exit.
To effectively manage visitor and temporary user access, QR code-based solutions are essential. The simplest solution is to replace the original card reader with a QR code reader. Both card swiping and QR code recognition send data to the controller for processing. However, this approach has a problem: the existing controller may lack visitor management functionality, or even if it does, it requires upgrading the access control software and controller.
Our solution involves replacing the reader with a QR code access controller all-in-one machine. When a card is swiped, a Wiegand interface is output to the controller; when a QR code is scanned, it is verified online (QR code data is sent to the visitor system, which determines permissions) and the door is opened. This allows the existing access control system to remain unchanged, and user and access permissions to remain the same. It satisfies the need for existing card-swiping users while adding a visitor system for visitor management. This highlights the necessity of adding a Wiegand interface to the QR code all-in-one machine.
Secondly, the addition of an RS485 interface to the QR code access controller all-in-one machine offers several advantages: First, as mentioned earlier, it connects to our AC037 security module via RS485, thereby improving the machine's security; second, it controls the turnstile opening and reads the turnstile status via the RS485 interface, enabling better control and status acquisition; third, it connects to elevator control equipment via the RS485 interface, allowing direct elevator access after swiping a card or scanning a code; and fourth, it outputs card numbers or QR code data to third-party industrial control equipment for expanded applications.
Cerberus's QR code access control machines all integrate Wiegand or 485 interfaces, which can meet the different scenarios demands.
