The usual way to connect them is to install a 3/8 X 3/8 mip by compression ell at the dishwaher and then a 5/8 X 3/8 compression by compression stop at the wall. And then install a length of 3/8 copper or a 5 ft stainless steel supply line (with the compression nuts already installed) between them.: At the dishwasher end I have a 90 degree 3/8 NPT. : Presently at the water supply I have a 1/2 Female copper fitting that is sweated to a Copper T fitting. The distance from washer to supply is approximately 5. What is the best way to interconnect the two items.