Communication Methods

This lesson covers how data is transmitted across networks, including serial vs parallel transmission, simplex/half-duplex/full-duplex modes, synchronous vs asynchronous transmission, bandwidth, and latency. These concepts are part of the OCR H446 specification section 1.3.

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Serial vs Parallel Transmission

Serial Transmission

In serial transmission, data bits are sent one after another along a single communication channel (wire).

Sender: [1][0][1][1][0][1][0][0] →→→ single wire →→→ Receiver

Feature	Detail
Speed	Generally slower than parallel (for short distances)
Distance	Suitable for long distances — less interference
Cost	Lower — fewer wires needed
Skew	No skew issues (only one wire)
Examples	USB, SATA, Ethernet, HDMI

Parallel Transmission

In parallel transmission, multiple bits are sent simultaneously along multiple wires.

Sender: [1] →→→ wire 1 →→→ Receiver
        [0] →→→ wire 2 →→→
        [1] →→→ wire 3 →→→
        [1] →→→ wire 4 →→→
        ... (8 wires for 8 bits at once)