1.5: Communication Hardware
Exam Board:
OCR
Specification:
2016 - Unit 1
The devices on this page are used to create or link together networks, allowing data to be sent between computer systems.
Hub
A hub receives data packets from a connected device and transfers a copy to all connected nodes.
Switch
A switch receives data packets, processes them and transfers them on to the device specifically listed in the destination address of the packet.
Modem
Modems are used to send data across the telephone network.
The telephone lines can only transfer analog signals so a modem is used to convert a computer's digital data into an analog signal.
Another modem converts the signal back to a digital format at the receiving end.
Router
Routers are used to transfer data packets between networks.
Data is sent from network to network on the internet towards the destination address listed in the data packet.
A router stores the address of each computer on the network and uses routing tables to calculate the quickest and shortest path.
Wireless Access Point (WAP)
Provides a link between wireless and wired networks. It creates a wireless local area network that allows WiFi enabled devices to connect to a wired network.
Combined Device
Also known as a hybrid device, this provides the functionality of multiple communication devices (e.g modem, router, switch and/or wireless access point) in a single device.
They can be more expensive than a single device but are more adaptable - if the routing part of the device fails it might still be able to function as a switch / wireless access point etc.
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However, you will see an increased performance from a standalone device rather than a combined one as standalone devices have more complex features (e.g. VPN support).
Network Interface Card
(Network Adapter)
A Network Interface Card (often shorted to NIC) is an internal piece of hardware that is required for the computer to connect to a network.
It used to be a separate expansion card but now it is commonly built directly into the motherboard (and known as a network adapter).
Wireless network interface cards allow wireless network connection.
Questo's Questions
1.5 - Communication Hardware:
1. What is the difference between a hub and a switch? [2]
2. Explain how a modem works. [3]
3. Explain the purpose of a router. [2]
4. What is a Wireless Access Point (WAP)? [2]
5. Describe what is meant by a 'combined device'. Give one advantage and one disadvantage of using a combined device. [3]