Understand that data is broken down into packets to be transmitted

📡 Types and Methods of Data Transmission

1️⃣ Types of Data Transmission

• Serial Transmission – data is sent one bit at a time over a single channel. Think of it like sending a message by tapping a single key on a typewriter. • Parallel Transmission – multiple bits are sent simultaneously over separate channels. Imagine a group of friends passing a stack of cards (bits) at once. • Wireless Transmission – data travels through the air using radio waves. Picture a radio station broadcasting music to your headphones. • Wired Transmission – data travels through cables (e.g., Ethernet). Like a train running on tracks.

2️⃣ Methods of Data Transmission

1. Unidirectional – data flows in one direction only. Example: a TV broadcast.
2. Bidirectional – data can flow both ways. Example: a phone call.
3. Full Duplex – simultaneous two-way communication. Example: a live chat.
4. Half Duplex – two-way but not at the same time. Example: walkie‑talkies.

3️⃣ Why Packets? 📦

Large data (like a video file) is split into smaller pieces called packets so it can be sent efficiently and reliably.

• Reliability – if one packet is lost, only that small part needs to be resent.
• Efficiency – packets can travel different routes and re‑assemble at the destination.
• Speed – multiple packets can be sent in parallel across the network.

4️⃣ Packet Structure

The total size of a packet can be expressed as:
$PacketSize = HeaderSize + PayloadSize + ChecksumSize$

5️⃣ Example: Sending a Text Message

1️⃣ Break into packets – a 200‑character message might be split into 4 packets of 50 characters each. 2️⃣ Send packets – each packet travels across the network, possibly via different routes. 3️⃣ Re‑assemble – the receiver uses the sequence numbers in the header to put packets back in order. 4️⃣ Check integrity – the checksum ensures each packet arrived correctly; if not, only that packet is requested again. 5️⃣ Display message – once all packets are received and verified, the full message is shown to the user. 📦➡️📶➡️🔁➡️??

6️⃣ Summary

• Data can travel in serial or parallel, wired or wireless. • Transmission can be unidirectional, bidirectional, full duplex, or half duplex. • Breaking data into packets improves reliability, speed, and flexibility. • Each packet contains a header, payload, and checksum. • The formula $PacketSize = HeaderSize + PayloadSize + ChecksumSize$ helps calculate packet sizes. 🔄💡