One of Michael Grave’s blog readers, has put the MagicJack Plus device under a (figurative) microscope. The device reportedly supports Speex when attached to a computer with the complementary soft client running.
Reader “BobB” says when the device is in stand-alone mode, the on-board SIP client only supports/advertises narrowband codecs. When attached to a computer with the accompanying soft client running, it advertises additional soft clients in the invite, including Speex at 16 kHz,PCMA at 16 kHz and PCMU at 16 kHz, plus G729 and iLBC.
ISR Computing (www.isrcomputing.com)– don’t know if BobB works for them – has a listing of the SIP conversations between the MagicJack Plus and a Digium Asterisk IP PBX.