Overview
A tool called a punch down tool is used to push the wire down firmly and properly into the slot. Some will automatically cut any excess wire off The exact size and shape of the tool blade varies by manufacturer, which can cause problems for those working on existing installations, especially when there is a poorly-documented mix of different brands.
Punch down blocks are a very quick and easy way to connect wiring, as there is no stripping of insulation and no screws to loosen and tighten. Punch down blocks are often used as patch panels, or as breakout boxes for PBX or other similar key phone systems with a 50-pin RJ-21 (Amphenol) connector. They are sometimes used in other audio applications, such as in reconfigurable patch panels.
Oftentimes a separate tool known as a spudger is used to remove small stray pieces of cut off wiring stuck within punch down blocks.
Read more about this topic: Punch Down Block