TY  - BOOK
AU  - Biswas, N.N.
TI  - Principles of telephony
SN  - 818527309-X
U1  - 621.385 
PY  - 1970///
CY  - New York: 
PB  - Asia Publication House, 
KW  - Applied physics
KW  - Group sector
KW  - Manual telephony
KW  - Telephone instruments
ER  -