Documents On-Line

http://docwiki.cisco.com/wiki/Internetworking_Technology_Handbook Internetworking Technology Handbook
http://docwiki.cisco.com/wiki/Internetwork_Design_Guide Internetwork Design Guide
 
   
AN-1298 Digital Modulation in Communications Systems http://www.web-ee.com/primers/files/5965-7160E.pdf Hewlett Packard