00398nam a22001217a 4500008004100000020001900041050002400060100002100084245004300105260005400148300003300202650004100235220624b        |||||||| |||| 00| 0 eng d  a97881122424867  aTK103.15b.D37 2006  aDas Apurbad1980  aLine communication system/cApurba Das  aNew Delhibnew age international publishersc2006  avii, 167p. :bill. ;c23.5cm  aTelecommunicationxSwitching systems