00477nam a22001577a 4500020001600000040000900016082001600025100002800041245002300069250001800092260004100110650003000151942001200181999001900193952010700212  a98141266357  cNUST  a621.385 BEL  aBellamy, C John9114122  aDigital Telephony:  aThird Edition  aNew York:bJohn Willy & Sons,c2003.  aDigital Telephony9114123  2ddccBK  c595516d595516  00102ddc4070aCEMEbCEMEcTEXTd2023-08-15l0o621.385 BELpCEME-41720.r2023-08-15w2023-08-15yBK