In order to keep the call costs for mobile calls as low as possible, there are various call-by-call (CbC) provider techniques. Call-through is a technique in which direct dialling via the mobile network
is bypassed and the call-by-call provider switches the call via fixed network connections. With a call-through connection, the mobile customer first dials the landline number of a low-cost CbC dial-in node. He can determine this with a mobile phone software. Via the application, the desired subscriber number is communicated to the switching node. This can be done by incorporating the desired subscriber number into the number used to ring the CbC exchange. The CbC provider forwards the call via the fixed network and collects the charges for this.