It is a survey to check your phone line for ADSL compatibility, if fiber-optic line is not used, and to confirm the line subscriber.
Line compatibility check is to survey the lines operated by NTT EAST/WEST. The check is on the desk survey, and customers' usage environment (how device is installed; wiring situation for customers' residence) will not be considered. Please note that ADSL may be unavailable due to causes (line quality, distance to local telephone office) which cannot be determined in this check.