Radia training3/27/2023 ![]() There are many examples of metro and tramway deployments in Europe. ![]() TETRA networks are extremely efficient for speech, providing up to four calls in one 25kHz channel, and with calls that are fast to set up and fast to clear, avoiding wasting airtime. ![]() Speech services are regularly used by station staff and maintenance crews. Telemetry from remote locations can ensure that the security and safety of unattended facilities are continuously monitored. The individual calling facilities are available in full duplex as well as the push-to-talk half duplex mode.Īs well as track-to-train applications, the data services are used for passenger information systems. TETRA has high performance group calls, with set-up times usually quoted as 300msec, for efficient staff communications (and efficient use of radio channels). The speech services are routinely used for on-board announcements and passenger emergency service support, as well as for communications between train and control room. Telemetry relating to the health of the train can be reported to control and maintenance systems and images from on-board camera systems can also be transmitted, for example in alarm situations. TETRA equipment is integrated with the on-board control and signalling systems, enabling the TETRA network to be used to report back location information from trackside and GPS location systems. The open interfaces have allowed different suppliers to build their own train dispatching and train control applications on top of the underlying TETRA network and terminal equipment. In metro and tramway applications, TETRA has been consistently used for speech and data centric applications. Around 15 companies participate in the TCCA’s Inter-Operability Process (IOP). Importantly, the services are specified in ETSI standards, which when combined with an independent interoperability testing regime overseen by the TCCA (TETRA and Critical Communications Association), allows a competitive multi-vendor supply process. The security mechanisms on TETRA were designed to be strong, with government use in mind, which is of increasing importance in the transportation market. A standardised interface on mobile and portable radios – the PEI (Peripheral Equipment Interface) – facilitates use of the radio as a modem to carry application data. Direct Mode Operation allows direct communication between on-train staff, or between on-train and trackside staff without the need for base station coverage nearby. More recently, the TETRA Enhanced Data Service provides much higher speeds for data without any compatibility or interference issues with the standard voice and data service. ![]() The Short Data Service is extensively used for messaging and location applications. A packet data service, allowing the transport of users’ IP packets, was an early enhancement to the standard, and provides a multislot packet data service that enables any number of timeslots from one to all four on a channel to be devoted to the data service. Group calls provide fast and efficient speech communication between drivers, control centres, maintenance teams, security organisations and many others. Full duplex speech calls allow safe driver-to-control room communications, as well as effectiveĬommunication with in-train passengers during emergencies. One of the advantages of TETRA is the integration of voice and data, allowing both critical control information and speech to be sent to and from the same radio terminal simultaneously. The TETRA standard was first released by ETSI in the mid-1990s, and was the first European standard for a digital trunked radio scheme intended to address the needs of business critical and mission critical users.įrom the outset, TETRA fulfilled many of the needs of the rail community and was adopted by several metros and tramways around the world for their communications requirements. Much has been written over the years to describe the success of TETRA in the transportation industry. ![]()
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