A dependent conduit is a Herschel conduit in which the input Herschel interacts with catalysts in the first few ticks. The standard interaction actually starts at T=-3, before the Herschel is completely formed. The Herschel is prevented from emitting its first natural glider; it instead produces a later output glider, twelve half diagonals away from the FNG lane. This is useful in cases where the previous conduit cannot survive a first natural glider emitted from its output Herschel. A rare example of an earlier interaction at T=-5 is the R49.
This term "dependent" is somewhat confusing, since it is actually the previous conduit that depends on the dependent conduit to suppress the problematic glider, or move and delay it. Dependent conduits such as the F166, Lx200, and R49 do not actually depend on anything. They can be freely connected to any other conduits that fit, as long as the output Herschel evolves from its standard great-grandparent. The Fx158 is the only known case where a conduit's output Herschel has an alternate great-grandparent, which is incompatible with either R49 or the dependent conduits' initial transparent block.