TY  - BOOK
AU  - Bellamy,John C
TI  - Digital telephony 
SN  - 9788126509294
U1  - 621.385 BEL  
PY  - 2011///
CY  - New Delhi : 
PB  - Wiley India Pvt Ltd., 
KW  - Network hierarchy
KW  - Digital modulation
ER  -