Polycom SoundStation Duo. Display: LED, Display resolution: 248 x 68 pixels. Voice codecs: G.711, G.722, G.729, iLBC, Dynamic range: 86 dB. Supported network protocols: IETF SIP (RFC 3261/ RFCs), FTP/TFTP/FTPS/HTTP/HTTPS. Security algorithms supported: 802.1x RADIUS. Input voltage: 100 - 240 V