Technology Options 
There is a wrong perception and lack of awareness about the features and value-added services that radio trunking can offer. Handsets are getting lighter and sleeker, while innovative voice and data capabilities are being added and offered by operators.

For example, various levels of user hierarchy can be defined for a given group of users. In case of emergency a ‘super user’ can break into an ongoing communication (between two users) by using special, predefined rights (say a password).

Two service options are available for enterprises—outsourcing and captive. Outsourcing is about availing the service through a service provider, whereas a captive approach allows an enterprise to bypass the service provider and seek the user license directly from DoT. Outsourcing is the best option for corporates for intracity communication within congested cities. Captive systems are best used by police, security forces, etc which cannot use public networks due to security reasons and have a dedicated technical team to maintain the network and also access to spectrum.

n Terrestrial Trunked Radio (TETRA): A European standard, defined by the ETSI, TETRA is a user-driven, open standard for next-generation digital mobile communications. Optimized to deliver voice, data and messaging services for one-to-one and complex group communications, TETRA is targeted at professional users in government agencies and commercial enterprises.

n Integrated Dispatch Enhanced Network (iDEN): A proprietary technology, iDEN combines the capabilities of four distinct communication devices into one handset, using a single network. This system enables digital telephone, two-way radio, short message service, and wireless modem service for flexible and efficient business communications.

n Logic Trunked Radio (LTR): LTR is a type of trunking logic first introduced in the market in 1979 by a company called EF Johnson. This system soon became the de facto standard in radio systems in the United States. This type of system is basically a form of mobile relay utilizing multiple radio channels, whereas the mobile units assigned to this system are always using a channel that is not busy or assigned to a user or active conversation. This is accomplished by mobile radio logic interpreting the commands of channel controllers connected by a high-speed data bus at the repeater site. In the dynamics of operation, the subscriber (user) gets the illusion that he is the only person on the radio as he does not hear anyone else on this system and most of the time has a clear access to the system. Major vendors offering products based on this technology are EF Johnson, Kenwood, Standard, Securicor/Midland, Vertex, Uniden and Motorola. 

n MPT 1327: An open standard defined by the British Ministry of Post and Telecommunications (MPT). As an open protocol, companies can make best-in-class components and have the pieces work together with other manufacturers. MPT 1327 uses a digital control channel with analog voice channels. The digital control channel supports several high-end system features including superior security and mobile data. The burst technology feature of MPT 1327 allows trunking system traffic to coexist with conventional traffic. No other protocol allows this kind of versatility without the expense of a high-end system. Because MPT 1327 is an open standard and uses analog voice channels, handsets typically cost less than handsets compliant with other protocols. Being open allows the operators the offer subscribers the freedom to use the terminals of any of the vendors like Simoco, Motorola, Nokia, Tait. Mobilkom India, for example, offers services based on this protocol in the NCR region, in technical collaboration with Rohde & Schwarz, a German vendor.