Communication Technology 📡
How messages get from sender to receiver — the components of communication, computer networks, and what your internet address actually means.
🎯 What you'll unlock this lesson
- ✅ Name the components present in every act of communication
- ✅ Recognize and use computer networks correctly
- ✅ Correctly select internet services for a given need
📡 The components of communication 5.1
Every act of communication — a teacher asking a question in class, or a phone sending a message — shares the same four parts:
Sender & Receiver
Who sends the message, and who it's meant for.
Message
The actual content being communicated.
Medium / Channel
What carries the message — air (sound), a wire, a radio signal.
Protocol
A shared "language" or set of rules both sides agree to use.
🕰️ A very short history of communication tech
Communication technology has always chased the same goal — faster, farther, clearer — from 1835's carrier pigeons and semaphore, through the telephone (1876) and radio (1888), to satellites (1958), ARPANET (1969), Wi-Fi (1990), the World Wide Web (1994), and on to today's 5G and IoT.
🃏 Key-term flashcards tap to flip
🌐 Computer networks 5.2
A network exists so devices can share resources — files, printers, an internet connection — instead of each device needing its own. Networks are classified by how far they reach:
📱 PAN
Personal Area Network — ~10m range. Bluetooth, infrared.
🏫 LAN
Local Area Network — one building or site. Wired or wireless (Wi-Fi/WLAN).
🌍 WAN
Wide Area Network — across cities or countries. The internet is the largest example.
🔌 Network devices
| Device | Job |
|---|---|
| Switch | Connects multiple wired devices within one LAN. |
| Wireless Access Point (WAP) | Lets wireless devices join a wired network. |
| Router | Connects different networks together — e.g. a home LAN to the internet. |
| Wireless router | Combines a router and a WAP in one device — the most common home setup. |
The full breakdown of network topologies (bus, star, ring, mesh) was on pages missing from the scan.
📶 Wireless health note
The textbook flags that the IARC classifies radio-frequency/EMF exposure as a Group 2B possible carcinogen, and recommends simple precautions — e.g. switching to airplane mode when a device is idle, and not carrying a phone against the body while it's transmitting.
🔢 IP addresses 5.3
Every device on a network needs a unique address to be found — an IP address, written as four numbers separated by dots, e.g. 202.168.1.192.
🎮 Interactive Domain Name Breakdown signature move
Type a domain, or tap an example, to see it split into third-level, second-level, and top-level parts.
🌍 Global TLDs
| TLD | Meaning |
|---|---|
| .com | Commercial |
| .edu | Education |
| .gov | US government |
| .org | Organization |
| .net | Network |
🇹🇭 Thailand 2nd-level
| Domain | Meaning |
|---|---|
| .ac.th | Academic institution |
| .co.th | Company |
| .go.th | Government |
| .in.th | Individual |
| .mi.th | Military |
- 1️⃣ Your school's network is down — what other ways could you connect to the internet?
- 2️⃣ What equipment does your school's network use to give every classroom Wi-Fi?
- 3️⃣ You need to send photos to a friend with no signal at all — what could you do?
- 4️⃣ How do you pair a wireless headphone with a phone, and how do you find and join a nearby Wi-Fi network?
🛒 E-commerce 5.4
E-commerce means buying and selling over the internet. It cuts overhead for sellers (no physical storefront needed), lets buyers compare reviews and prices, and covers everything from marketplaces like amazon.com and ebay.com to travel sites like trivago.co.th.
- 1️⃣ Reverse-image-search a photo of a location to identify where it was taken.
- 2️⃣ Register an email account and send an attachment to your teacher, CC-ing two classmates.
- 3️⃣ Set up a video call with 4 or more people.
- 4️⃣ Find a local shop that accepts cashless/QR-code payment.
The rest of §5.4 Internet Services (search engines, email, social media covered earlier in the section) and all of §5.5 Cloud Computing were on pages missing from the scan.