STU-II

It permitted up to six users to have secure communications, on a time-shared (e.g.: rotating) basis.

It was made by ITT Defense Communications, Nutley, New Jersey.

According to information on display in 2005 at the NSA's National Cryptologic Museum, the STU-II was in use from the 1980s to the present.

The display also stated that the STU-II B is the standard narrow band secure telephone.

The last was a secure telephone in a briefcase, of which 110 were built in the 1980s for use by senior government officials when traveling.