The Switch/Load Unit (SLU) consists of a standard VME type enclosure and a custom high current backplane. The E6198A SLU comes with 21-slot for plug-in cards while the E6218A supports only up to 6-slots. The TS-5020 can be configured with either a full size or a mini SLU, while the TS-5040, due to space constraint, only allows the mini SLU.
