TY  - BOOK
AU  - Freeman, Roger L.
TI  - Practical Data Communications 
SN  - 0471392731
U1  - 004.6 
PY  - 2001///
CY  - New York : 
PB  - John Wiley, 
KW  - Data Transmission Systems
N1  - YY
UR  - https://eaklibrary.neduet.edu.pk:8443/catalog/bk/books/toc/0-471-39273-1.pdf
ER  -