A crimping tool is a tool designed to crimp or connect a connector to the end of a cable. For example, network cables and phone cables are created using a crimping tool to connect the RJ-45 and RJ-11 connectors to the end of the cable. In the example picture below, this crimper is capable of crimping a RJ-11 (6-Pin) and RJ-45 (8-Pin) connectors and also includes a wire cutter near the handles that can be used to cut phone or CAT5 cable.
To use this crimping tool, each wire is first placed into the connector. Once all the wires are in the jack, the connector with wires are placed into the crimping tool, and the handles are squeezed together. Crimping makes the plastic connector puncture and hold each of the wires, which prevents the wires from falling out and for data to be transmitted from the connector to each of the wires.