Old thread I am waking up. I am having the repeat issue with the B&K CT receivers with RS232. Trying to switch over from IR control, and vol ramping jumps 2 DB at a time. More importantly like mute which if repeated twice mutes and unmutes. I have the lateset update for the MSC-400 and hoped that older issues were fixed. Any input or fixes other that press and hold stated above? Sorry if this has been answered but this is the first old thread that relates to my situation.