Not sure if this is accurate but spoke with Horizon directly today. I bought the DX4S w/o AVC and it will not bind with any receiver other than dsmr. CS said both the DX4S and DX4R Pro will only work with dsmr and no more backwards compatiblity. I told him I wanted to return it and initially he said "no" but after explaining FALSE ADVERTISING to him on the Horizon website showing it working with either DSMR or DSM2, they are letting me return it for a full refund!!!