TY  - BOOK
AU  - Held, Gilbert
TI  - Understanding Data Communications 
SN  - 0672300052
U1  - 004.6 
PY  - 1991///
PB  - Sams, 
KW  - Data Transmission Systems
KW  - Digital Communication
N1  - YY
UR  - https://eaklibrary.neduet.edu.pk:8443/catalog/bk/books/toc/0-672-30005-2.pdf
ER  -