Abstract: A modular, multi-channel, contiguous output, multiplexer which combines directional filters with the diplexed output of two multi-channel multiplexers, each covering a contiguous frequency band, i.e., one is a low multiplexer and the other a high multiplexer, and one or more quasi-elliptical directional filters after the diplexer output to cover the hole left by the diplexer crossover. A preferred embodiment may essentially consist of: 1) a 12 channel contiguous multiplexer, either a hybrid directional and manifold type multiplexer or a short circuited multiplexer, covering frequencies, e.g., in the range from 3.7 GHz to 4.2 GHz; 2) a 6 channel contiguous multiplexer spanning frequencies substantially in the range from 3.42 GHz to 3.62 GHz; 3) a diplexer including a 6 section Chebyshev filter, with a passband of frequencies, e.g., in the range of 3.4 to 3.620 GHz, and about 30 dB attenuation at 3.7 GHz, and an 8 section Chebyshev filter passing frequencies, e.g., in the range of 3.7 GHz to 4.