Instant messaging Mobile communication systems 6 Text messages (Telephone systems) 2 Armed Forces 1 Cell phones 1 Cellular telephone systems 1 Communication and technology 1 Communication in organizations 1 Deaf 1 Digital communications 1 Emergency medical services 1 Equipment and supplies 1 Malay language 1 Means of communication 1 Military administration 1 Multimedia systems 1 Personal communication service systems 1 Public key infrastructure (Computer security) 1 Security measures 1 Technological innovations 1 Telecommunications devices for the deaf 1 Usage 1 Wireless communication systems 1