000 00317nam a2200133Ia 4500
082 _a005.71
_bHEL
100 _aHeld,Gilbert
245 _aUnderstanding data communications
250 _a5th
260 _aNew Delhi
_bTechmedia
_c1998
300 _a504p.
650 _aComputer Science
650 _aInformation Technology
999 _c2230
_d2230