Cylink STX-2400X Voice/Data Encryption Units - Easy hook-up to phone (4-pin modular plug) - 198 bit key - Clear/Secure voice/data - keyed lock - SEEK key exchange or manual key loading - User's manual - ac power supplys These are the same as the STX 9600X currently sold by Cylink at $3000/unit except the data transfer rate is 2400 bps instead of 9600 bps. Good voice recovery. Like new condition. Asking $450.