Walkie talkies are the handheld tools popularly known as two way radios also. This system functions on the principle of half duplex, wherein messages can be sent and received one at a time. Users have to press the button present in walkie talkie to send the message and have to release it to receive the message. Their functionality is not bound to any time duration or size duration. Users can send longer messages also. Walkie talkies are mostly used in malls, defence offices, commercials and also for personal use in large distances.
If we recall the old days, our parents use to make trunk calls. You must have wondered ample of times thinking about the meaning. Trunk calls follow Trunking systems wherein from single frequency, multiple connections can operate. This enables easy and secured sharing of information within the organization. Though there are many modes of communications available in the world due to technological development, the base for these modes remains the signals of the network. There is a huge indoor and outdoor coverage problem in rural or congested areas. Repeaters amplify the existing signals from the nearby base transceiver system and provide fair coverage and voice quality.
Continuous growth have evolved the production of DMR Radio (Digital mobile radio) providing services of optimum privacy to the confidential conversations and also providing good coverage and voice quality. Terrestrial trunked radio (Tetra) is yet another radio derived from ETSI. It works on two RF's (radio frequency) and used mainly by government projects, hospitals and commercial offices.