Catalyzes electroneutral exchange between L-arginine and L-ornithine (PubMed:23144255). Can also efficiently translocate L-alanine (PubMed:26324452). May function in vivo as a L-arginine/L-alanine exchanger in a pathway together with the arcT gene, which is found adjacent to the arcD2 gene in the ADI gene cluster (PubMed:26324452). L-arginine(out) + L-ornithine(in) = L-arginine(in) + L-ornithine(out) Deletion does not affect the growth enhancement observed in the presence of high L-arginine in different growth media, and uptake activities are slightly reduced. Belongs to the amino acid-polyamine-organocation (APC) superfamily. Basic amino acid/polyamine antiporter (APA) (TC 2.A.3.2) family.