A type of networking device that you can use to monitor the flow of data in serial lines. Data taps provide an easy way to connect monitoring equipment such as data scopes to serial interfaces such as RS-232.
These serial connections are used for a variety of networking purposes, including connecting data terminal equipment (DTE) such as servers and routers to data communications equipment (DCE) such as modems and CSU/DSUs (Channel Service Unit/Data Service Units) for implementing wide area networks (WANs); connecting dumb terminals to asynchronous mainframe hosts; and connecting servers to plotters and other serial devices.
Data taps generally display network traffic in binary, hexadecimal, or character format and are used for troubleshooting various kinds of network connections.
A data tap is essentially a three-way connector in which the third connector interfaces with the test equipment. For RS-232 serial lines, data taps come in a variety of configurations, with mixtures of male and female DB-9 and DB-25 connectors.
Graphic D-8. Data tap.