Properly designed access control system means the warranty of an entreprise security of staff and assets. But in order to meet this purpose, all system components should have their high security and high performance features. Including the data transfer protocol, as the integrity of lines and completeness of incoming information depend on.
Disadvantages of Wiegand
For a long period of time the most common wired interfaces for interaction between a reader and ACS controller Wiegand and Clock & Data remained. Despite their considerable disadvantages, which the experts include:
- One-pointedness. The data transmitted only in the direction from the reader to the controller, without the ability to track the reader’s status. The device may be broken or be stolen, and the controller does not handle these situations and continues to inform the operator that everything is OK.
- «Point to point». One controller port is connected to only one reader, and in other cases the conflict is possible.
- The lack of encryption. Temporal and electrical characteristics of interfaces are well-known, and it allows attackers to emulate the operation of the reader and to transmit «the all doors code» to the controller easily.
Weak points of Wiegand and Clock & Data have led to the emergence of more effective alternatives – Open Supervised Device Protocol. The OSDP has been designed for secure data exchanging in its protected form, encrypted with AES-128 algorythm. Its physical basis is RS-485 interface. The data transfer is performed via differential signal, providing greater noise immunity, and also increases the length of the segment «controller – reader» up to 1200 meters.
Advantages of OSDP
Consider other features of the protocol.
- Based on mutual authentication: when communicating, devices need to «trust» each other using a unique set of keys. In case of error or «suspicion» of interference, the communication session is interrupted, and the keys are destroyed without delay.
- Thus, an interactive user experience is provided. It is possible not only to get the information from the reader on the number of a card processed or a PIN code entered, but to display the information regarding the events without the connection of additional interfaces onto LCD monitor. This, for example, provides an opportunity to understand why a person is not allowed the access: there is no right to pass/reader is in its standby mode/the card has not been read. And taking into account the working time, it is convenient to fix the time of passage onto the display.
- Suitable for different types of readers, exit buttons and relay modules. In addition, it is easy to be installed. When implementing into an existing system, it is possible to use existing cable infrastructure connecting one cable up to 128 devices. But if talking about a new facility developping, that will save money within its installing. If Wiegand requires at least four wires, and the management of led and audio indication – three, OSDP just four are enough.
The OSDP is open to manufacturers of readers, controllers and software that may extend the functionality on one’s own. The Protocol is actively gaining «the card» segment access control, but at the same time it is not easy to find the biometric reader or controller supporting it. “BioSmart s.r.o” has implemented support for OSDP to the equipment line of Biosmart biometric system in the May of 2018. Nowthat, the company offers devices enabled to act both as readers to transmit data under the OSDP into the third-party system, and the role of management via process controllers.
The use of OSDP open standard leads to a wide spectrum of compatible solutions allowing to upgrade and to expand the system finished easily. The introduction of BioSmart biometric controllers increases the level of security within an enterprise, as it provides a customer with its confidence regarding safety of the investments.
BioSmart PV-WTC may be used as biometric reader in existing access control system
Third-party equipment may be connected to PV-WTC via OSDP