It means you can connect 2 radios to one amp and do SO2R without a 2nd amp N2RJ On Fri, Apr 21, 2017 at 6:11 PM <sq7d at onet.pl> wrote: > SO2R amp? What does it mean? > My Quadra with smart swith is so2r amp too. > > > Matt > SQ7D/SN7D >