Level B - NATO SDIP-27

(formerly AMSG 788A) and USA NSTISSAM Level II

Tempest Level B is the next highest NATO standard, also known as "IMMEDIATE". This standard applies to equipment that can not be heard from a distance of over 20 meters. This Tempest standard applies to equipment operating within NATO Zone 1. This standard protects equipment both from 20 meters of unobstructed distance and a comparable distance through walls and obstacles.