Phone in very good condition. Power supply in good condition.
The Secure Terminal Equipment was the U.S. Government's replacement for the STU-III secure telephone, beginning in 1994. Encryption is provided by a Fortezza Crypto Card (KOV-14 or Enhanced KSV-21), not included, which fits in the PCMCIA slot on the front. The STE was backwards compatible with the STU-III. It was replaced by the Sectéra vIPer Universal Secure Phone, which again has integrated encryption, and does not require a Fortezza card or the STU-III's Crypto Ignition Key (CIK). The vIPer is backwards compatible with the STE. This "Office" model is the most common.
See L-3 Communications Secure Terminal Equipment with STE sleeve for another example, with STE Sleeve.
L3 STE.