Types and Methods of Data Transmission
How data is chopped into packets and sent down a wire — one bit at a time or several at once.
- Click the stages below in the order they happen.
//Packet switching, step by step
The message is split into packets. Each packet is numbered and sent, and each can take a different route depending on how busy the network is. They may therefore arrive out of order, so the receiver uses the packet numbers to put them back together. Anything missing is requested again.
//Serial vs parallel — distance decides
Serial sends one bit at a time down a single wire: slower per moment, but reliable over long distances. Parallel sends several bits at once down several wires: faster, but over distance the bits arrive at slightly different times (skew) and get mixed up. That is why parallel is only used over very short distances, like inside the computer.
//USB in one paragraph
USB is serial transmission. Benefits: the plug only fits one way, it is a universal standard, it is fast, and it can charge the device and install drivers automatically. Drawbacks: the cable is limited to about 5 m, and older versions have a lower transfer rate.
KEY TERMS
CHECK YOURSELF
1.Why is parallel transmission unsuitable over long distances?
2.A phone call, where both people can talk at once, is an example of:
3.Why might packets arrive out of order?