00531nam a2200181 a 450000500170000002000150001708200150003210000240004724500450007126000530011630000220016969000200019169000240021196400190023599700180025499900170027295200600028920251203091825.0  a013200478X  a004.6bmar  aMarkley, Richard W.  aData communications and interoperability  aLoNew DelhionbPrentice-Hall Internationalc1990  axiv,236p.c23 cm.  aNetwork systems  aData communications  bENGcdefg_  a65882 LIBSC C  c54037d54037  00104070aPUbPUd1998-04-08l0o004.6 marp65882yBK