This document describes the call transfer feature of the Popfax fax service. It allows users to transfer incoming calls to their Popfax number to other phone numbers, including mobile phones. The user must purchase an option pack and enable call transfer in their account settings. When call transfer is enabled, calls will be forwarded to the selected number but faxes will no longer be received through Popfax. Per minute charges apply to transferred calls deducted from the user's account balance.