Patch panels are groups of ports used to connect lines between communications and electronic devices. Connections are made manually with small patch cords, and are easier to wire than automatic switches. Wireless patch panels are also available. These devices closely resemble conventional patch panels, but are able to make both radio frequency (RF) data connections and standard patch cord connections. Typically, patch panels contain faceplates and/or ports that are shielded from electromagnetic interference (EMI) and radio frequency interference (RFI). Some devices mount on walls. Others mount in equipment racks such as standard 19” units. Devices that are certified by Underwriters Laboratories (UL) comply with that organization’s published standards for safety.