A Hoffman box is an enclosure used to secure electrical and/or network equipment, and is used in such things as a protected distribution system. - wikipedia.org/wiki/Hoffman_box
I am trying to perfect Pet-Pals for J2ME distribution on camera phones and I needed to pass a gnarly part of the Java Verified process performed by NSTL. To make my own Hoffman box I put the Nokia E71 into a small sauce pan inside a large sauce pan inside a larger pot with lids over all inside the oven. This combination gives great signal isolation. I do NOT recommend you cook a casserole at the same time.