[Asterisk-Users] three way call using sip

[Eric Wieling]

Paul Rodan wrote:

> The BT100's do support conferencing, most SIP phones do. But how does your
> Asterisk connect you to the PSTN? Through a Zap interface? If so, what kind;
> or through a VoIP provider like BroadVoice, NuFone, LookieLoo, VoipJet,
> VoicePulse? 
> 
> You basically need to make sure your Asterisk server has access to more than
> 1 line. If it does, then you should be able to 3-way call without any
> problems.

According to this only the BT102D supports "conferencing" aka 3-way 
calling:

http://www.grandstream.com/Product_Spec.pdf