CDOT Telephone Exchange System

CDOT telephone exchange is designed by India.
CDOT stands for Centre for Development of Telematics
Telephone exchanges are used for interconnecting Telephones.
There are two types of telephone exchanges.
One is Local Exchange. where your telephone is connected.
Other one is DTAX(Digital trunk automatic Exchange). It is trunk exchange.
used for interconnecting long distance calls.

cdot telephone exchange.
This local exchange is where your telephones are terminated.

In olden days, trunk calls were put through by telephone operators
using trunk exchnages. When the trunk excchanges becaome automatic, it was called as TAX (trunk
automatic exchange). The TAX were previously working using electromagnetic relays and finally now it has become fully electronic and digital. Hence now these trunk exchanges are  called as DTAX which means digital trunk automatic exchange.

Do you know?

India was purchasing  telephone exchanges from foreign countries because there is no r&d in india this field. Then came Mr.pitroda . Pitroda founded and served as chairman of C-SAM^] The company maintains its headquarters in Chicago with offices in Singapore, Tokyo, Mumbai . He  decided he might help modernize India's telecommunications system. In 1984, for the govt of india, he designed CDOT exchange.  in 1984. 

)But now in 2013, india has almost 100% importing telephone exchanges from foreign countries  as there is no proper r&d in india.

a cdot exchange