TY  - BOOK
AU  - Cannon,Don L.
TI  - Understanding communications systems / 
SN  - 0672270161
U1  - 621.380413 
PY  - 1989///
CY  - Indianapolis, IN
PB  - Howard W. Sams & Co., 
KW  - Telecommunication
N1  - Includes index
ER  -