00398nam a2200157Ia 4500003000400000005001700004008004100021020001800062040000600080041001200086082002200098100003000120245005300150260002500203300001200228OSt20250120144739.0231217s9999    xx            000 0 und d  a9788120307131  c0  aEnglish  a621.381537  VIS;7  aViswanathan, Thiagarajan. 0aTelecommunication switching systems and networks  c2002bPHIaNew Delhi  axx, 583