What does tap mean?

Data is transmitted through optical cables; Superficially speaking, the concept of tap is similar to the meaning of "tee", that is, the original flow of normal traffic, at the same time, a share out for monitoring equipment analysis and use. In fact, this is just the simplest tap concept, the current technology development has produced many kinds of taps: There are many links can be brought together tap, there is a link flow into several regeneration tap, a bypass tap, a matrix tap Switch and so on, can no longer use the word "tee" to briefly summarize. In terms of function, tap's emergence is a huge revolution in the whole monitoring/monitoring field, which fundamentally changes the access mode of the monitoring and analysis system, which makes the whole monitoring system have a complete and flexible solution.

What does tap mean?