I have been trying out VOIP Stunt via PC and it works great. VOIP Stunt currently offer unlimited call the land lines in Malaysia, UK, USA and Australia and to enjoy the free call and low call rates to many countries, I have purchased and installed a Linksys ATA Adaptor and configure it to work with VOIP Stunt.
The Linksys ATA offer two lines and each line can configure to work with one VOIP Stunt Account and by connecting these two lines to the keyphone system in the office, fellow office workers will be able to call using them and hence enjoy substantial saving especially on calls to other cities in Malaysia.
We have so far tested with two lines with one streamyx connection account and the quality is extremely good.
Not to forget that to enjoy those free calls, there is a need to make a payment of 10 Euro per VOIP Stunt account that will last you up to four months if you do not make calls to places that VOIP Stunt charge minimal fee.