Instant messaging Text messages (Telephone systems) 19 Computer software 16 Development 16 Mobile communication systems 15 Application software 12 Internet telephony 10 Bluetooth technology 6 Internetworking (Telecommunication) 6 Wireless communication systems 6 Multimedia systems 5 Anti-theft devices 4 Automobiles 4 Computer network protocols 4 Computer networks 4 Computer programs 4 Database management 4 Electronic alarm systems 4 Java (Computer program language) 4 Security systems 4 Telephone switching systems, Electronic 4 Cellular telephone systems 3 Automatic control 2 Business communication 2 Cellular telephone 2 Data processing 2 Design 2 Design and construction 2 Electronic mail messages 2 Electronic mail systems 2