The ComNet C3 is a 1 RU (1.75") high 19-inch rack-mountable card cage unit capable of mounting up to three ComNet ComFit 1.0-inch wide modules. Ideally suited to those applications where rack space may be limited, the C3 may also be used in desk-top installations by the addition of user-installed rubber feet on the bottom of the cage and removal of the two rack-mount adapter brackets. Available in either a black anodized or satin silver finish, the C3 is provided with one external 120-240 VAC power supply with a 12 VDC at 2A output, and includes reverse polarity protection. Two separate isolated DC inputs are provided for mission critical/high reliability applications where power supply redundancy is required. ComNet ComFit PoE (Power over Ethernet) modules may also be used, by replacing the power supply with a +48 VDC unit, and connecting the supply output to the DC power input of each PoE module. Cooling is by natural air convection, eliminating the need for unreliable and noisy cooling fans, or periodic air filter maintenance. The C3 is designed for long-term reliable operation in harsh industrial environments, and may be deployed in most out-of-plant installations, such as those found in intelligent transportation systems and factory automation/control applications. Plug-and-play design ensures ease of installation, and any module may be hot-swapped without any impact to the operation of the other modules within the card cage.