00277nam a2200109Ia 4500008004100000041000800041082001700049100001500066245002800081260004400109300001400153220530s9999    xx            000 0 und d  aeng  a623.733bBIS  aBiswas N N  aPrinciples of Telephony  aNew DelhibUBS Publishers Pvt Ltdc2003  a138 PbPB