Data Compression in Modems
Used to increase the throughput rate of data by encoding redundant data strings
Example: Lempel-Ziv encoding
- Used in V.44
- Creates (while transmitting) a dictionary of two-, three-, and four-character combinations in a message
- Anytime one of these patterns is detected, its index in dictionary is sent (instead of actual data)
- Average reduction: 6:1 (depends on the text)
- Provides 6 times more data sent per second
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