VHF system to be taken off the network in phased manner

The Technical Services Wing (TSW) of the Tamil Nadu Police is set to install a new system called Terrestrial Trunked Radio (Tetra) to replace the conventional Very High Frequency (VHF) system in Coimbatore and Madurai.

Tetra is now being used by select sections of the Chennai Police. Tetra, formerly known as Trans-European Trunked Radio, uses the time division multiple access (TIME) system. The police now use the VHF radio communication system.

Often, lack of efficient transmission, clarity in transmission and television channels picking up VHF signals, defeated the confidentiality of communication. Hence, the decision to go in for Tetra, sources in the technical services wing said.

Under the present communication system, when a VHF handset is lost and lands in the hands of the common man or mischief-mongers, confidentiality of the conversations is lost. But Tetra ensures complete confidentiality.

At present, Coimbatore city police have two VHF channels: one for law and order and crime and another for traffic management.

Tetra will be introduced in the cities of Coimbatore and Madurai as a combined project at a cost of Rs. 4.5 crore.

Installation

The installation works are nearing completion. Coimbatore has 15 police stations spread over 230 square kilometres. TSW has already installed repeater towers at Saravanampatty, Kovaipudur and atop the four-storeyed Police Commissioner’s Office. Tetra, expected to completely phase out the VHF system, comes with effective and efficient network management. There is also provision for call record logs. Since Tetra comes with a Global Positioning System (GPS), location of the handset is possible.

In short, the police personnel on duty cannot cheat on superiors by giving wrong location information. The equipment also has an internal dialling facility which enables the officer/personnel to maintain confidentiality of the information being transmitted. It also has a short messaging service, officials said.

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