The IBM EMR and EMR II Keyboards were the final variant of the Model F/XT, featuring different cables and connectors and shielding around the internal logic board. These keyboards were designed to be compliant with the shielding specification of codename TEMPEST, a NATO-recognised U.S. National Security Agency specification regarding methods of spying and protecting against spying with electronic equipment. In particular, these keyboards were designed to not radiate electromagnetic emanations to counter Van Eck phreaking.