1) Call 1) Telecom 2) Telecommunication 3) Telephone 
Telephony (i {respell|tə|LEF|ə-nee}) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is intimately linked to the invention and development of the telephone. Telephony...
• (n.) The art or process of reproducing sounds at a distance, as with the telephone.
a form of telecommunication primarily intended for the exchange of information in the form of speech.
Te·leph'o·ny noun The art or process of reproducing sounds at a distance, as with the telephone. 
Telephony refers to the reproduction of speech at a distance from the source.
telephony 1. The transmission of sound between distant stations, especially by radio or telephone. 2. The technology and manufacture of telephone equipment.
The science and practice of telecommunications.