Certification Examinations 1.489 Electronic data processing personnel 1.307 Computer networks 591 Study guides 546 Microsoft software 361 Telecommunications engineers 205 Computer technicians 176 Maintenance and repair 166 Internetworking (Telecommunication) 112 Security measures 112 Operating systems (Computers) 110 Microcomputers 104 Microsoft Windows (Computer file) 93 Computer security 86 Microsoft Windows server 73 Automobile mechanics 72 Routers (Computer networks) 61 Automobiles 57 Java (Computer program language) 54 Database management 49 Examinations, questions, etc 49 Microsoft .NET Framework 44 Telecommunication 38 TCP/IP (Computer network protocol) 34 Development 33 Oracle (Computer file) 33 Switching systems 32 Application software 29 Client/server computing 29