Simple Win32 / SIP Library with API needed

Archived from groups: comp.dcom.voice-over-ip (More info?)

Hi!

I have an application written in Delphi/Win32 and I need to add
functionality allowing a phone-call via SIP to be made.

I am therefore looking for a SIP library that will provide me with
methods / functions to:

A) Place a call
B) Transfer a call
C) Detect and answer an incoming call.

I don't need any fancy graphicy phone thingy I just need a library that
will do the clever SIP stuff deal with codecs etc and an API to it!
Win32 and Linux compatibility would be good, but otherwise Win32 is my
main priority right now.

The library can be commercial (I don't mind paying something
reasonable... open-source even better!) but should not require me to
pay Per-Seat royalties. I can find plenty of H.323 solutions but I need
a SIP one.

Also I wonder about codecs! Is G.711 generally good enough to make a
call to a local SIP/PSTN gateway or do I need something better? But
will this cost?!

Any help much appreciated!

Cheers,

Tim