1) sip¨crfc 3261 (and 2543) conformant ua, stun rfc-3489 sdp-rfc 2327 2) call setup/ tear down, call transfer, calls handling, call timer, call forward, instant messaging, presence caller id and name tag,redial through last dialed numbers, call from phonebook and call history, call hold/resume 3) g.711 a-¦ìlaw, g.729ab, echo canceller, dtmf(in/out band), packet loss concealment, vad and comfort noise, volume control 4) dial tone / busy tone / call-waiting tone / ring-back tone / network busy tone 5) ringer, volume-adjustable, customized ring tone, vibration 6) total 21keys, including 4 soft-key 4 rocker switch keys with select key 7) lcd: 1.4 inch b/w stn 96*65 lcd, backlight. led: link / incoming call indication e-mail:danny@vnetphone.com url: www.vnetphone.com skype id: cnwxdkj