A network interface device includes a base, a cover and a circuit board secured in the base. The circuit board includes terminations for input and output communication lines. Each pair of input and output communication lines corresponds to a single standard telephone line, a high speed data line or other type of line. The communication line terminations may be implemented as insulation displacement connectors, and the cover may include projections on its inner surface such that closing the cover also closes the insulation displacement connectors on the circuit board. For each communication line, the circuit board may include a subscriber bridge which establishes a breakable connection between the input and output line terminations via traces in the circuit board. In fixed wireless, fiber-to-the-home (FTTH) and other similar applications, the circuit board may also include terminations for input and output power lines, and the base and cover may be extended to accommodate an uninterruptible power supply. The power supply supplies the input power line to the corresponding termination on the circuit board, and the output power line is supplied to a power input of a remote unit in a fixed wireless system or other electronic unit external to the network interface device. The circuit board may also include power protection circuitry for protecting against surges on the input and output communication and power lines.