Note
Electronics World, Sep 1959, p. 92.
QST, Oct 1959, p. 208. "Available February 1960."
QST, Jan 1960, p. 168. "Available in March 1960"
Although Allied showed a T-400 at the 1960 WESCON show in Las Angeles, the unit probably never actually sold. As of this writing (2024), no examples have been found by collectors, and none have shown up on ebay.
Technical description. CQ, Feb 1961, p. 56.