Telefoniliin

Telefoniliin, or telephone line, is the physical circuit that connects a subscriber’s telephone to the telephone network. In traditional landline systems, telefoniliin consists of a copper two-wire local loop that carries analog voice and the signaling used to set up and terminate calls. The line runs from the subscriber’s premises to a local exchange (central office), where it connects to switching equipment. The local loop is typically powered from the exchange with direct current, allowing older phones to operate without a separate power source.

Voice on the telefoniliin is transmitted within the audible frequency range and is handled by network elements that separate and combine transmitted and received signals, using a hybrid circuit to keep voice directions distinct. Ringing signals, supervisory signaling, and other control functions are defined in the local loop and central office equipment.

Over time, telefoniliin can refer to several underlying transport methods. Copper two-wire analog lines are still common for traditional POTS (Plain Old Telephone Service). Digital lines such as ISDN or DSL use the same copper pair to carry voice alongside data. Fiber-based connections, including fiber to the home (FTTH) or fiber to the node, terminate the line at an optical network unit. In many regions, VoIP services run over general data networks and may replace or augment traditional telefoniliin for voice traffic.

In modern telecommunication, telefoniliin is often discussed in relation to the public switched telephone network (PSTN), regulatory frameworks, and the ongoing shift toward IP-based and wireless voice services. It remains a foundational concept for fixed-line communication and universal service considerations.