Preferred Internet Provider provides two forms of voice solutions -

Preselect Discount Fixed line to mobile and long distant calls. 
With this service all calls to Mobile phone or non local calls are billed through 
PIP at our incredible rates. 
There are no contracts and line ownership remains with your current provider.

AND

Voice Over IP Telephony services (VOIP).
After FREE calls to interstate offices or friends and family overseas ?
This is the product for you. VOIP allows you to make calls over the Internet.
If the recepient of your phone call has the same technology, your call is free
otherwise you are charged the discounted PIP phone call fee (see above).