<I believe that's just an attenation control; puts a 75 ohm resistor before <the monitor.. Like the Pad control on a sound mixer I think, just brings <the level down to avoid damaging things... or something ;P < <Kevin No! It's for those system that use terminated cables rather than random impedences. For long cables they should be matches at each end to the nominal impedence of the cable and the swich turns on the resistor that does that. Just like the loads used for thin eithernet(or thick). Allison