Meaning of Internet Telephony

Internet telephony (also IP telephony) refers to the transmission of telephone calls over the Internet – via a telephone, using software on a laptop or PC or with a smartphone. A large number of households in Germany use Internet telephony via the DSL connection or the cable TV network. In the meantime, IP technology has almost completely replaced the old telephone networks (analog, ISDN).

  • A large number of households in Germany use Internet telephony via DSL or cable connections.
  • Many DSL providers have been using IP technology for a long time. The standardized IP network has now almost completely replaced the old networks (analog and ISDN).
  • Internet telephony can also be used directly on the PC or smartphone.

Internet telephony: Telephoning in the IP network

The technical foundations of Internet telephony were created in the 1970s and 80s. With VoIP (Voice over Internet Protocol), the voice data is not transmitted over analog lines, but over the Internet. Internet telephony experienced a breakthrough from around the middle of the noughties. At this point in time, most households were already provided with a DSL connection that guaranteed good voice quality. In 2004 Skype came onto the market, one of the most popular software solutions for direct internet telephony on the PC.

With IP telephony, the telephone is not connected to a TAE socket on the wall or an ISDN box, but to a VoIP-capable cable modem or a DSL router. Older telephone devices can also continue to be used with IP connections without any problems. They are also connected directly to the wireless router . With VoIP, the spoken word is converted into data that is sent over the network in small packets. The recipient’s end device collects the packets and converts them back into speech.

If the connection is too slow, the packets can arrive with a long delay or be lost completely – this can lead to interruptions and delays in the voice connection. However, the transmission rates are so high nowadays that the voice quality is often better than with conventional telephone calls in the analog network. A DSL connection with a constant upstream rate of 120 kbit / s is sufficient for voice transmission. IP telephones with HD voice functionality can improve the voice quality even further.

Networks in transition: IP conversion for private customers

A large number of households in Germany already use Internet telephony via the DSL connection or the cable TV network. Most DSL providers have converted their analog connections for private customers almost completely to the more modern IP technology in recent years. The conversion will only take longer for business customers and should be completed by 2022.

The reason for the IP changeover is the outdated and inconsistent network structure. Keeping three different networks (analog, DSL, ISDN ) in operation in parallel turned out to be time-consuming and expensive for the provider. For example, so-called transfer points were necessary to connect the networks to one another. The great advantage of the uniform IP network is a simpler infrastructure, which brings enormous cost savings with it. The network providers are now bundling the technology at a few central points. Another benefit of the IP changeover: the freed-up frequencies can be used for more DSL bandwidth.

Direct internet telephony on the PC

A popular variant of Internet telephony is telephoning via a PC or laptop. A telephone program and a headset consisting of headphones and a microphone turn the computer into a so-called softphone. Most laptops today come with a webcam and microphone as standard.

Telephone customers also save costs with direct internet telephony. Because there are no extra charges for calls such as Skype – even if the person you are talking to is abroad. With an IP telephone or a computer with the appropriate VoIP software, subscribers in the conventional fixed or mobile network can also be called. For this, however, fees are due again from the respective provider.

Internet telephony with your smartphone

Short for ITEL by abbreviationfinder, Internet telephony is also possible using a smartphone app. Customers should, however, find out beforehand which mobile phone providers allow VoIP in their network. In addition, the transmission rates in the cellular network should be kept in mind so that there is no loss of quality or even a disconnection.

There is also the option of using VoIP with a smartphone in a WLAN network. Anyone who logs into a WLAN at home or on the go can talk to other users for free using Internet telephony apps such as Skype. However, if there is too much user activity in the WLAN, the call quality can suffer as the upstream rate is shared among all users. In addition, the VoIP apps often consume a lot of power – so users should keep an eye on the battery of their smartphone.


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