Integration is key to creation of the successful security ecosystem. Integration, finally means to operate each and every device on a single platform be it desktop, mobile or cloud application. All connections at the central location are controlled unimanously and all changes or alerts appear at one location, so easy to guard and control. Successful, flawless & bugfree integration means a perfect project. Many factors play a role in integration, from SDK to API in software while as hardware protocols from VFC Voltage Free Contacts to serial ports, Integration is neither a hectic nor an easy task especially when to be done for the first time. Integration of access controls with video surveillance or with intruder alarm detection systems or integration of all physical security systems to form a single platform based solution.
Hardware Integration for access controls
Integration of hardwares is solely dependent on the type of protocols, communication techniques & data transfer modes. There are various hardware protocols used for integration like de facto protocol wiegand, Serial communication ports like RS485 & RS232, I/O relay ports, Voltage free contacts or often called dry contacts (NO/NC) and recently introduced OSDP (Open Supervised Device Protocol) . Each protocol has a specific application in the integration of devices. Like OSDP has an advantage over Wiegand, RS485 is used for long range communication and RS232 is generally used for debugging & firmware upgrades.
| RS232 | RS485 | Wiegand |
| Serial port for short distance communication. | Serial port for long distance communication. | De facto protocol for communication |
Wiegand Interface & protocols in access controls
Most of the security hardware comes with a de facto protocol called Wiegand with a certain bit width and is widely used to connect the peripherals. The physical interface of the wiegand interface consists of three wires reffered as Data lines (DATA0 & DATA1) & ground in combination with one ground. Data0 (D0) is low data while Data1 (D1) is high data. The communication protocol used for data transmission using the Wiegand Interface is referred to as Wiegand protocol. In general application in case of access controls wiegand is 26 bit wide format is used but can be varied based on the devices. Depending on the reader protocol, the two wire connection is made with existing contact on the control panel & vice versa. The wiegand communication depends on the specific reader and the controller interface, the bit width needs to be the same to ensure proper communication. Wiegand is easy to implement with no encryption. The protocol layers are further designated as below
| Leading bit parity | Facility code | Credential Data | Trailing bit parity |
Facility codes play a very important role in physical access control systems in terms of enhancing the security of the site.
RS232 protocol serial port for integration
RS232 is one of the earliest and oldest communication protocols widely used in access controls for integration. RS232 stands for the Recommended Standard 232. It is the serial communication protocol used for the transmission of data normally in medium or small distances. Dating back to 1960’s of its introduction in the market, it was used for debugging and small scale communication. In physical access control systems, the units are generally controlled, tested and debugged using the RS232 serial ports. These ports act as an interface between the serial port of the computer and the physical access control panel. The communication parameters to be considered for the RS232 communication mode transmission rate is baud rate which is generally set as 9600 but can be 2400 4800 19200 38400. Higher the baud rate means faster data transmission speed with less interference . Generally only one device can be connected using the RS232 port for communication with a distance of 3-13 Meters for better results.
RS485 protocol serial interface for integration
RS485 is a widely used serial port for communication and integration in physical access controls systems engineering. The limitations for communication in RS232 are eliminated by using the RS485 serial port. The distance of communication using the RS485 port exceeds 1000Meters and can extend to 1200Meters ideally ( 1.2KM). The number of devices connected on the same wire is more than one and can be limited based on the product, the general load limit is 32. The speed of communication starts from from 35Mbit/s to 100kbit/s. The quality of wire matters a lot in communication using RS485 mode, better quality means better transmission & achievable results. RS-485 differential line consists of two signals i.e: A : low for logic 1 and high for logic 0 and B: high for logic 1 and low for logic 0. The RS485 is an electrical interface and in most of the applications RS485 uses the signal levels, the speed, format, and protocol of the data transmission which is technically not specified by RS485. Interoperability is the key to success for RS485 communication interface in the integration of access control systems. RS485 is widely utilizing the access controls with the Building Management Systems, this port is made available with the turnstile gate systems.
OSDP (Open Supervised Device Protocol) for access controls
The latest communication protocol in physical access control systems, with very salient features in eliminating the errors, bugs and technical issues associated with Wiegand communication protocol. OSDP offers encryption at high end AES128, constant monitoring to protect against the threats, advanced user interface & long distance communication, interoperability by method of communications among manufacturers, solutions & devices. OSDP is categorized as OSDP V1 & OSDP V2 formats, complying with the established standards. OSDP V2 is the superset of OSDP access controls V1 and has secure channel encryption, smart card communication with biometric reader support if needed with the timeout near 200ms, and busy port reply. The secure channel is an encryption technique used by OSDP V2 compliant devices to protect the communication between controllers and readers at the highest level.
Access control panels with voltage free contacts
Let us assume a relay which has a normally open or normally closed set of contacts, practically not connected to any source, mechanical or electrical, is called dry contact or voltage free contact (VFC). The contacts are energized by external or intrinsic sources based on available pulses. The VFC’s (Voltage Free Contacts) find a very great place in the integration process of access controls and other physical security equipment. Every electro magnetic or electric lock and semi automatic turnstile works using solenoids, and the energizing of solenoids allows the opening or closing of the turnstile gates. The NO (Normally Open) & NO (Normal Closed) in combination with the ground are utilized for the integration purpose, as the energizing pulses decide the factors of integration as why & what for integration is to be made. The output signal generated is fed to third party devices or equipment to enhance the desired results. The best examples as cited are electromagnetic locks etc. In case the dry contacts are not available, then the external relays are used to develop the functions as required. The external relays are available with the delay pattern as well.
API (Application Programming Interface) for integration
API is the software or a piece of software that connects computers with other softwares. Technically the document or standard that describes how to build or use a connection or interface is called an API specification. The piece is used by the programmer who incorporates it in the software. We can say it is an intermediary document that allows two softwares to talk, hence a medium of integration. There are different types of API’s like Open APIs, Internal APIs, Partner APIs, Composite APIs, RESTFUL, JSON-RPC, XML-RPC, and SOAP. Ech API type is good for integration. Web API are accessible using http interface protocols, OpenAPI’s are available for developers with least possible restrictions, Internal APIs are used by private developers and the data is not widely available for general public, Composite API allows developers to access certain endpoints. REST (representational state transfer) is a web API architecture. It includes the client-server architecture, statelessness, cacheability and the layered systems.
SDK (Software Development Kit) for access controls
SDK is used for the integration of access controls and other third party devices.Some times called as “devkit”, Software Development Kit is different compared to the API. SDK is the complete collection of the software development tools in one installable package. It is the set of tools , completely relevant documentation & associated papers, the code samples, necessary processes, and set of instructions that helps and permits the software programmer and developers to create software applications on a specific platform. SDK includes the testing tools that make it possible for developers to find and fix errors. SDK comes with extensive documentation that can be incredibly useful when it comes time to debug the application. SDK helps create better integration of the products and easier reducing the security risks. Physical access controls systems can be integrated with other devices and softwares using the SDK. Software development kits make integration very easy and affordable.
The various hardware interface ports & software kits are used for the integration of access controls among themselves or third party devices.
| RS485 | These are serial interface, and can extend the data transmission unto 1.2KM (1200meters). The access control panels with RS485 are capable for connecting with control unit with load of 32 units on the same transmission line. The quality of cable matters a lot in such interface for better data transmission. These interfaces are most of the time used for integration with BMS etc. |
| RS232 | Used for short distance communication and practically for one unit per port. The distance is also limit to few meters, in general such ports are used for debugging purposes. |
| Wiegand | This is a defacto protocol, active in market since 1960 and is widely used in Access control systems for communication and Integration |
| SDK | This is a software development kit or called as DEV KIT also. This helps in integrating the access control panels practically with every equipment |
| API | This is Interface kit or we can call as utility, it helps in integrating a certain port or portion with the web application or other utilities. |
| VFC | Voltage Free Contacts, NO/NC are practically available with every control panel and are much used for integration with similiar ports. |
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