Same-country-code rule

Outbound voice calls from a ReachCell number may only be placed to destinations in the same country as the source number. A US number can only call US numbers; an India number can only call India numbers.

Routing a local SIM to a local destination is a legitimate local call. Routing a local SIM to an international destination would constitute SIM-box / interconnect-bypass fraud, which is illegal in virtually all jurisdictions.

A cross-country attempt returns HTTP 422 with code CROSS_COUNTRY_CALL_NOT_PERMITTED. SMS is not subject to this restriction.