Ours is the 3 button type (A, B, C) with A inside speakers and C outside speakers.
When I brought ours home, DW was complaining the inside speaker volume was much too low. I suggested she push button 'A' and 'C' before we went camping.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.