Hi Nathan, I knew there were two jacks but I didn't know that they could be used in that way. I also use the Standard C5900A and it can be set to use the internal for both sides, an external for both sides, an external for one side and the internal for the other or like I have it, two external speakers and I mounted them where I knew which I was hearing. That was a great help when I was monitoring simplex on one side and was using input output on a repeater where I was getting horrible interference from the hospital and paging companies. 73 and thanks. Btw, I am using the matching Kenwood speaker. I will keep my eyes open for the Motorola speakers. Walt and GEB dog Opus WA4QXT New London CT mailto: [log in to unmask]