Satellite:

Satellite transmission is one important symbol of revolution in communication technology. Besides transmitting picture and sound over long distances, it has revolutionised telecommunicaiion, telephone, telegraph etc. Already, from a number of towns in India, we can make long distance telephone'calls  not only to other towns within the country but also to several towns in other countries through direct dialling, i.e.,  without the help of a  telephone operator. In fact, for remote places like Leh, Port-Blair and Aizwal  

which are separated by Jea or difficult terrain, satellite transmission offers the only viable afid feasible means of linkage. multi-purpose satellites for expanding the communication  network in the entire country. INSAT-  1  A was launched in  1982,  but it developed technical snags. INSAT-  1B  was then  . launched in  1983, and INSAT-1C in  1988. These satellites have been providing widespread coverage to the media,  in addition  to many other services like in the fields of mete~~ology,resource surveys, telecommunication,  and research etc.