00300nam a2200109 a 450000500170000002000150001708200200003210000200005224500560007226000440012830000180017220251203091940.0  a8175150637  a621.38,bD, Lan  aLangley, Graham  aTelecommunications premier: System and applications  aNew DelhibGalgotia Publlicationsc1996  a283p.c26 cm.