More features

Call transfer - YES
Call hold - YES
Audio record - YES (Record Audio Mix in Auto or Manual Mode )
DTMF supported
RFC2833 / SIP INFO Method
Audio TuningWizard - YES
Multiple Call 5 lines (requires account authorisation for simultaneous calling)
Microphone & Speaker Device Selector - YES
Microphone & Speaker Volume control - YES
SIP UDP Support - YES
Acoustic Echo Cancellation - YES
Outbound Proxy supported - YES
STUN supported - YES
Jitter Buffer - YES
Call History - YES
Address book - YES
Call Timer - YES
Auto update - YES
Credit Balance Display - YES
Import/ export from outlook 2003+
Import / export contact from CSV file (outlook 2003+)

Know issues: An issue with audio settings for external devices. Please use only with default audio card for the time being.