TY  - BOOK
AU  - Ali, Syed, R 
TI  - Digital switching systems 
SN  - 978-0-07-048390-3 
U1  - 621.382 ALI  
PY  - 2008///
CY  - Tata mcgraw hill company Ltd 
PB  - New Delhi 
KW  - TELECOMMUNICATION
ER  -