Secure Terminal Equipment (STE) is the U.S. Government's current , encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128k bits per second 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

RS-232

In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...

 port. STE is intended to replace the older STU-III

STU-III

STU-III is a family of secure telephones introduced in 1987 by the NSA for use by the United States government, its contractors, and its allies. STU-III desk units look much like typical office telephones, plug into a standard telephone wall jack and can make calls to any ordinary phone user...

 office system and the KY-68

KY-68

The TSEC/KY-68 DSVT, or Digital Subscriber Voice Terminal, is a US military ruggedized, full- or half-duplex telephone terminal with a built-in encryption/decryption module for secure traffic. Converting voice to digital form, it can communicate voice or data at 16 or 32 kbit/s...

 tactical system. STE sets are backwards compatible with STU-III phones, but not with KY-68 sets.

STE sets look like ordinary high-end office desk telephones and can place unsecured calls to anywhere on the public switched telephone network (PSTN). There is a PC Card

PC Card

In computing, PC Card is the form factor of a peripheral interface designed for laptop computers. The PC Card standard was defined and developed by the Personal Computer Memory Card International Association which itself was created by a number of computer industry companies in the United States...

 slot in the STE that allows a Fortezza

Fortezza

Fortezza is an information security system based on a PC Card security token. Each individual who is authorized to see protected information is issued a Fortezza card that stores private keys and other data needed to gain access...

 Plus (KOV-14

KOV-14

The KOV-14 Fortezza Plus is a US National Security Agency-approved PC card which provides encryption functions and key storage to the Secure Terminal Equipment and other devices...

) Crypto Card or KSV-21

KSV-21

The KSV-21 Enhanced Crypto Card is a US National Security Agency-approved PC card that provides Type 1 encryption functions and key storage to the STE secure telephones and other devices....

 Enhanced Crypto Card to be inserted. When an NSA

National Security Agency

The National Security Agency/Central Security Service is a cryptologic intelligence agency of the United States Department of Defense responsible for the collection and analysis of foreign communications and foreign signals intelligence, as well as protecting U.S...

 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.

Models

• Office - The Office STE is the most widely used STE and provides voice and data access to ISDN (Integrated Services Digital Network) and PSTN (Public Switched Telephone Network) telecommunications systems.
• Tactical - The Tactical STE is similar to the Office STE but can also access the TRI-TAC (TRI Service TACtical) network and has a serial EIA-530A/EIA-232 BDI (Black
  RED/BLACK concept
  The RED/BLACK concept refers to the careful segregation in cryptographic systems of signals that contain sensitive or classified plaintext information from those that carry encrypted information, or ciphertext ....
  
   Digital Interface) port.
• Data - The Data STE provides remote access for voice, fax, data and video-conferencing. This model has two serial EIA-530A/EIA-232 BDI ports and allows for data transfers to multiple destinations.
• C2 - The C2 STE is similar to the Tactical STE but C2 has modified software for use with its Tactical Terminal Locking Handset mechanism.
• STE-R - Similar to the Data STE, the STE-Remote provides dial-in access to the Defense Red Switch Network (DRSN).
• VoIP - The STE now has Voice over Internet Protocol (VoIP) capability, available as an upgrade to the current models, or built in to some new models.

As of 2007, a typical STE terminal cost about $3100, not including the crypto card.

External links

• The NAVY INFOSEC WebSite on STU-III and STE