Possesses tyrosine phosphatase activity. H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate Monomer; active form. Homodimer; inactive form (By similarity). Interacts with CNTN3, CNTN4, CNTN5 and CNTN6. Detected in brain, lung, kidney, heart, liver, skeletal muscle, spleen and testes. It is developmentally regulated in the brain. Belongs to the protein-tyrosine phosphatase family. Receptor class 5 subfamily.