Communication and Information Technologies
Domain 3: Communication and Information Technologies
This domain tests how messages and data move through systems and how information technologies store, process, and protect them. Expect questions on communication models, encoding, bandwidth, digital signals, networking, cybersecurity, and technical communication.
Core concepts
- A communication system includes a source, encoder, transmitter, channel, receiver, decoder, and destination, plus feedback and noise.
- Analog signals vary continuously; digital signals use discrete values, usually binary. Digitizing involves sampling and quantization.
- Bandwidth is capacity, often bits per second; latency is delay. More bandwidth does not automatically reduce latency.
- Compression reduces file size; lossless preserves exact data, lossy discards detail.
- Networks use protocols and layered models; the Internet is a network of networks. Cybersecurity controls include authentication, authorization, encryption, patching, and backups.
- Technical communication includes drafting, CAD, graphics, photography, and technical writing; standards make drawings unambiguous.
Worked example
A temperature sensor sends readings to a classroom display. Source: sensor. Encoder: microcontroller converts voltage to a digital value. Transmitter: Wi-Fi radio. Channel: wireless link. Receiver/decoder: display unit. Destination: screen. Feedback: acknowledgments and retransmission requests. Noise: interference from other devices. If a 60 MB file is sent over 10 Mbps, convert: 60 times 8 = 480 Mb; 480 divided by 10 = 48 seconds. The reasoning matters: use bits consistently, and remember that real throughput is lower because of overhead.
Traps
- Mixing bits and bytes.
- Equating bandwidth with latency.
- Omitting noise or feedback from the model.
- Treating digital as automatically error-free.
- Ignoring security and ethical use of data.