telephone instruments

Description In telephony, ringdown is a method of signaling an operator in which telephone ringing current is sent over the line to operate a lamp or cause the operation of a self-locking relay known as a drop. Ringdown (a) is used in manual operation, as distinguished from dialing, (b) uses a...

Description A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are not in the same vicinity of each other to be heard directly. Introduction to the product industry(TELECOM INDUSTRY) The Indian telecommunication industry is...