Filled cable

In telecommunication, a filled cable is a cable that has a nonhygroscopic material, usually a gel, inside the jacket or sheath.

Note 1: The nonhygroscopic material fills the spaces between the interior parts of the cable, preventing moisture from entering minor leaks in the sheath and migrating inside the cable.

Note 2: A metallic cable, such as a coaxial cable or a metal waveguide, filled with a dielectric material, is not considered as a filled cable.

Source: from Federal Standard 1037C and from MIL-STD-188