To create a powerful and standardized solution the ISO CALM concept (Communication Access for Land Mobile) was introduced. ISO CALM is a family of international Standards (ISO 2121x) which shares a common architecture, common network protocols and air interface definitions for wireless communications. ISO CALM supports multiple media, like 2nd and 3rd Generation Cellular, 5.9 GHz Active Microwave and Active Infrared communications.

Infrared Transaction System ATLAS

The ISO CALM based IR transaction sub-system ATLAS is the hard- and software part of the ETC system that is responsible for the toll payment based either on monetary manipulation of a Contactless Smart Card (CSC) located E-purse (pre-payment) or forwarding customer / vehicle data held on the smart card or OBU to the backend for further account based money withdrawal. This is done by means of active IR data transmission from on board units over IR transceivers to the control unit.

The IR transaction sub-system ATLAS itself is modular designed and divided into the hardware sub-modules:

• Transceiver
• Control Unit 
  
  

These sub-modules communicate with the On Board Unit IS®OBU and optional Contact-less Smart Card IS®CSC in the vehicle.

IR Transceivers

The overhead mounted EFKON infrared transceivers communicate with an EFKON on board unit (OBU) which is mounted inside a vehicle. The communication medium is infrared light using the most advanced ALNRS (Ambient Light Noise Reduction System). The device is connected to and controlled by an EFKON control unit.

• EFKON transceiver for multilane applications. With a special sunshield it is also suitable for single lane applications.
• EFKON transceiver used in a special supporting system in a satellite based ETC environment.
• EFKON transceiver used for mobile IR data communication.
  
  

IR Control Units
Controlling the entire IR subsystem of a lane.

• EFKON  CU for single and multilane applications.
• EFKON CU used in a special supporting system in a satellite based ETC system.
• EFKON CU used in vehicles for mobile enforcement. 
  
  

Typical Application Environment

• Electronic Toll Collection (ETC)
• Parking & Access Control
• Traffic Telematics
   
  
   

• Active, bidirectional high-speed communication technology
• no backscatter solution
• High bandwidth
• No radio license required
• Coexists with all Radio Based Equipment
• Balanced Power Budget due to bi-directional Active Communication
• Works with tinted windscreens
• Works under all weather conditions
• No fading and reflection effects due to incoherent radiation