Interfaces and Standards

Compliance with standards and norms in urban road traffic technology is a prerequisite for smooth data exchange.

Outstations – Communicating with the Field Device

We have developed the following technologies for communicating with field devices, the so-called outstations:

Sitraffic Canto

Sitraffic Canto communication technology (Communication in Advanced New Technology in Outstations), offers a particularly efficient process for transmitting traffic data and, besides that, enables older controllers to be connected to modern control centers.

The use of TCP/IP on the control center side leads, however, to a much more flexible utilization of today's IT infrastructures, such as OTN or fiber-optic networks.

Canto supports all new functions of the Siemens Sitraffic C900 traffic controller and of the Sitraffic Scala traffic control center. The transmission protocol is distinguished by the following characteristics:

  • Use of the latest communication media such as DSL and GPRS

  • Standardized IP network planning

  • Cable-saving connection (Partyline)

  • Security in data traffic with VPN tunnel and PKI encryption in the controller and the control center


OCIT (Open Communication Interface for Traffic) is an open standard for road traffic control systems. Siemens actively promotes the OCIT Initiative. Our centers/central devices and control devices support this open standard.

VDV Standard for Public Transportation Prioritization

The VDV standard is used to register and deregister public transportation vehicles for giving priority to public transportation at traffic lights. This standard allows wireless communication between the public transportation vehicle and the intersection controller. The information is then used by the local traffic actuation to give priority to public transportation.


The TLS (specifications for the supply of roadside controllers) describes a communication standard for interurban freeways. Via the TLS interface the system receives traffic information, data on current sign displays as well as environmental data that are important for urban traffic management.

Instations – Communication between Centers

The following technologies are used for communicating between the various centers:


The comprehensive interface, OCPI (Open Content Provider Interface) allows for the quick and cost-efficient integration of other systems. Interface converters also enable communication via other standards such as WanCom, TLS, DAV, DATEX II, VDV etc.


OCIT-C (Center to Center) are standardized interfaces between central components and systems, and replace the previous interfaces, i.e. OCIT-I process data and OCIT-I supply data.


TMC (Traffic Message Channel) is a standard for the transmission of location-related, digital traffic reports. Our control centers can receive and generate, edit and forward digitalized traffic reports in the TMC format.


DATEX II is a European standardization initiative for the various different applications in the area of traffic data and information. Based on this standard, the Siemens headquarters support communication for selected projects.