The landline network was originally a purely circuit-switched telephone network, over which individual participants' lines were (originally manually, and later automatically) connected together to make calls. With increasing digitisation and the demand for data transmission, the fixed-line network has developed into a universal, integrated services network. Today it is possible, via landline broadband Internet access, for example via DSL, to achieve bandwidths of many megabits per second. The protocol that is primarily used for the transfer of services is IP (Internet Protocol). Modern networks are capable of transporting both data and the spoken word via IP. The advent of Voice-over-IP (VoIP) technology has meant that both consumers and providers only need a single infrastructure over which all services can operate. Even the reception of television programmes can be implemented over the IP network.
The merging of data and voice transmission via the fixed-line network opens up completely new possibilities. A computer can become a fully-fledged phone, connecting call participants with a simple mouse click. In addition, telephone systems can be fully operated as a cloud service through the data network, making it possible to have as many telephone connections as desired, without the need for the customer to purchase and maintain costly hardware in their premises.