http://www.state.gov/documents/organization/87246.pdf
A Canadian or Mexican citizen seeking admission as a treaty national (TN)
professional shall be treated as if seeking classification under INA
101(a)(15). Therefore, if he or she fails to meet all of the requirements of
the TN visa category, the basis of visa refusal is INA 214(b). The maximum
validity of a TN visa is three years, but note that a TN visa may be issued for
lesser validity based on the proposed activity or the applicant’s request. The
admission period of a dependent (TD) shall coincide with the TN principal's.
(See 9 FAM 41.59 N5 for definition of "temporary").
A Canadian or Mexican citizen seeking admission as a treaty national (TN)
professional shall be treated as if seeking classification under INA
101(a)(15). Therefore, if he or she fails to meet all of the requirements of
the TN visa category, the basis of visa refusal is INA 214(b). The maximum
validity of a TN visa is three years, but note that a TN visa may be issued for
lesser validity based on the proposed activity or the applicant’s request. The
admission period of a dependent (TD) shall coincide with the TN principal's.
(See 9 FAM 41.59 N5 for definition of "temporary").