I'm referring to a J model and the channel has nothing to do with frequency, its a video channel. There are two video out puts one for the LH display bus and the other for the RH display bus. Either one of the channel can be selected as 'Partial' from the AMU. The manuals doesn't say anything about purpose of a 'Partial' selection. By default both channels are "Full'. I will appreciate it if you can help me out.