The CSI-100 permits the use of existing, but unused 75 ohm video coaxial cable as an alternative to running new cable for a keypanel connection. The CSI-100 is a bi-directional; single-channel coaxial interface, which passes digital audio and control between KP-32 series keypanels, and CSI-200 coaxial interfaces connected to RTS intercom matrices. Installation of the CSI-100 is quick and simplified with no user settings. Existing KP-32 series keypanels can be retrofitted with the CSI-100 in about 15 minutes. In addition, KP-32 series keypanels can be ordered with the CSI-100 option already installed.