IP telefon, Grandstream, BT200

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IP telefon, Grandstream, BT200, Perfekt

Grandstream BT-200 sip (internet) telefonfor gratis eller billig telefon opkald.
Support SIP, TCP/UDP/IP, RTP/RTCP, HTTP, ICMP, DNS, DHCP, NTP, TFTP protocols
Support NAT traversal via STUN & symmetric RTP
Interoperable with various 3rd party SIP end user device, Proxy/Registrar/Server, and gateway products
Advanced Digital Signal Processing (DSP) to ensure superb hi-fidelity audio quality
Advanced and patent pending adaptive jitter buffer control, packet delay & loss concealment technology
Support popular vocoders including G.723.1 (5.3K/6.3K), G.729A/B, G.711 (a-law and u-law), G.726, G.728, and wide-band G.722 (Model 102D). Dynamic negotiation of codec and voice payload length
Support standard voice features such as Caller ID Display or Block, Call Waiting, Hold, TransfForward, FLASH, in-band and out-of-band DTMF (RFC2833), Dial Plans, off-hook auto dial, configurable emergency dialing (e.g., 911), early dial, click-to-dial
Support 3-way conferencing (Model 102D), full duplex hands-fredomain acoustic echo cancellation (pending), redial, call log, volume control, voice mail with indicator, downloadable ring tone (pending)
Support Silence Suppression, VAD (Voice Activity Detection), CNG (Comfort Noise Generation), Line Echo Cancellation (G.168), and AGC (Automatic Gain Control)
Support DIGEST authentication and encryption using MD5 and MD5-sess.
Provide easy configuration thru manual operation (phone keypad and Web interface) or personalized automated provisioning via central configuration file for mass deployment.
Support for Layer 2 (802.1Q VLAN, 802.1p) and Layer 3 QoS (ToS, DiffServ, MPLS)
NAT-friendly remote software upgrade capability (via tftp) even from behind firewalls/NATs.
Support for fail-over SIP server and DNS server (pending)