Corded and cordless fixed-line handsets used against the ear couple magnetically with hearing aids to ETSI ES 200 381-1 and are marked with the ETSI ETS 300 381 T symbol; wireless handsets held to the ear provide coupling as ETSI ES 200 381-2 specifies (TIA-1083-A and ANSI/IEEE C63.19 respectively are accepted as compliant).
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.