TY  - GEN
AU  - Bates,Regis J.
AU  - Bates,Marcus
TI  - Principles of voice & data communications 
SN  - 0072257326
U1  - 621.382 
PY  - 2007///
CY  - Boston
PB  - McGraw-Hill Irwin
KW  - Telecommunication
N1  - Includes index
ER  -