High Quality Content by WIKIPEDIA articles! 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. The KY-68 can operate via civilian and military switches in either encrypted or un-encrypted mode, or point-to-point (encrypted mode only).