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Fallback solutions are available with manual or automatic activation and deactivation. ### Fallback solutions in telecommunication technology In the telecommunications field, fallback solutions are mainly used in the professional sector. However, private telecommunications equipment can be protected with fallback technologies. Many organisations have a fallback system in place for their Internet connection, as it is often essential for the company to be able to operate their daily business. This system would mean having a wired Internet connection from their usual provider, complemented with a second connection from another provider as a fallback solution. Mobile technologies with a high [bandwidth](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/bandwidth), such as LTE or UMTS, are often used as a fallback. Many Internet access routers will be able to detect the failure of the primary connection autonomously and automatically switch to the fallback option. Also, when the primary connection is operational again, the switch back to using that can take place automatically. As use of the fallback connection often results in higher costs, it is usually advantageous to reconnect to the the primary line at the earliest opportunity, once it is operational again. Many domestic Internet routers are also able to support fallback connections. They can be expanded with a variety of devices, such as UMTS or LTE surfsticks, through which, if necessary, an Internet connection can be established, via the mobile network. ### Telephone systems and fallback Some [Voice over IP (VoIP)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) telephone systems have an alternative [ISDN](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/isdn) connection, which can be used as a fallback. If the VoIP connection is lost, the telephone system routes calls via the ISDN network. If a company uses modern, virtual [cloud telephone systems](/gb/en/products/cloudya), it is usually sufficient to protect the Internet connection with a fallback solution, in order to access the cloud. If the fallback solution restores the connection to the Internet, the cloud telephone system is accessible and usable. ### Related Articles ### Integrated Services Digital Network (ISDN) In telecommunications technology, the abbreviation ISDN stands for the technical term "Integrated Services Digital Network" and refers to a digital standard for telephone networks. As the name implies, various types of communication services can be transmitted through this kind of network. In addition to voice calls, ISDN allows packet-switched or circuit-switched data transmission and fax transmission. In some countries, ISDN technology has taken over from analogue telephone networks, integrating all types of services into a common network for the first time. This digitisation has also enabled digital ISDN phone lines to be made available to end users. In comparison to an analogue connection, an ISDN subscriber line offers a whole range of advantages. The basic ISDN line allows multiple phones or communication [devices](https://web-production.nfon.com/gb/products/devices), with different numbers ([MSNs](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/msn)), to operate and use two parallel connections simultaneously. In addition, the ISDN connection also offers higher data transfer rates to an analogue connection using a modem, for example, when accessing the Internet. To utilise the ISDN line, end users need special ISDN-capable phones or faxes. The use of so-called [A/B converters](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/a-b-interface), linking analogue devices to a digital connection, is common. Meanwhile, other techniques such as DSL or cable connections are used for connecting to the internet. 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