Secure Terminal Equipment (STE) is the U.S. government's current (as of 2008[update]), encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128 kbit/s and are all digital. The greater bandwidth allows higher quality voice and can also be utilized for data and fax transmission through a built-in RS-232 port. STE is intended to replace the older STU-III office system and the KY-68 tactical system. STE sets are backwards compatible with STU-III phones, but not with KY-68 sets.[1]
STE sets look like ordinary high-end office desk telephones and can place unsecured calls to anywhere on the public switched telephone network (PSTN), as well as secured calls on it via the phone's backwards compatible STU-III mode. There is a PC Card slot in the STE that allows a Fortezza Plus (KOV-14) Crypto Card or KSV-21 Enhanced Crypto Card to be inserted. When an NSA configured Crypto Card is present, secure calls can be placed to other STE phones. STE phones are "releasable" (unlike STU-III sets). All cryptographic algorithms are in the crypto card.
Newer STE sets can communicate with systems that use the Secure Communications Interoperability Protocol (SCIP) (formerly Future Narrowband Digital Terminal (FNBDT)). There are upgrade kits available for older units.[2]
As of 2007, a typical STE terminal cost about $3,100, not including the crypto card.[2]
