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[+44 330 383 8000](tel:+443303838000 "+44 330 383 8000") ![](/images/getstarted-writetous-navbar-int_ZY7MOf.webp) ### Write to us Fill out our request form. Our experts will respond as soon as possible. [Write to us](/gb/request-information "Write to us") ### Analogue telephone lines [Dialling using an analogue telephone line](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/analogue-telephone-lines#section-3) [Data transfer on an analogue telephone line](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/analogue-telephone-lines#section-4) [Analogue phone lines and modern cloud telephone systems](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/analogue-telephone-lines#section-5) # Analogue telephone lines An analogue telephone line enables, via an installed wall socket, the connection of an analogue device, such as a telephone, modem or fax machine, to the telephone network. Unlike the digital [ISDN system](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/isdn) or a [Voice-over-IP (VoIP)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) connection, the signals from an analogue terminal are directly transferred to the telephone network in analogue form. Voice information is translated from sound waves into electromagnetic signals of a similar frequency. As a rule, an analogue telephone line only requires a traditional two-wire cable connection. ### Dialling using an analogue telephone line With an analogue telephone line, the information about the dial-up connection, as well as the voice information, are transferred down telephone line in parallel, so special dialling procedures are used. The older method is so-called pulse dialling, which dates from the time of switching centres with rotary dials. The individually transmitted pulses turn the dial into a certain position that ultimately establishes the connection. The pause between the pulses ensures the correct control of the various rotary dials. Current analogue telephone lines use the system known as multi-frequency dialling (DTMF). Each key tone produces two defined frequencies (DTMF - Dual Tone Multi Frequency), which initiate the dialling process at the telephone switching station. ### Data transfer on an analogue telephone line Since analogue telephone lines only allow the transmission of analogue signals, to transfer data, it is necessary to convert digital data into analogue information. This task is performed by a modem (modulator-demodulator). At the transmission end it turns the digital signal into an analogue one and the, at the receiving end, back into digital again. Owing to the limited frequency spectrum in the analogue telephone network the maximum data transmission bandwidth is limited and not comparable to other transmission methods, such as DSL. ### Analogue phone lines and modern cloud telephone systems Even though [modern cloud-based telephone systems](/gb/en/products/cloudya) that use [Internet Protocol (IP)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/ip-address) and function completely digitally by transmitting the voice information using VoIP, it is still possible to connect conventional analogue devices to them. To enable this, adapters are used, which are connected to the network and translate the analogue signals into VoIP data. Often, these adapters are integrated into access routers, allowing multiple analogue devices to be connected at the same time. ### Related Articles ### Voice over Internet Protocol (VoIP) **What is VoIP?** The **Voice over Internet Protocol,** also called IP telephony, is a method of communication for making calls over a broadband Internet connection as an alternative to regular calls made over an analogue phone using the [PSTN](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/pstn). These VoIP calls can happen entirely over the Internet but where required, gateways also link to the PSTN. This means that VoIP users can still connect to anyone with a telephone number including local, mobile, and international numbers. VoIP services can be accessed from a computer with a so-called [softphone,](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/softphones) from an IP phone, from a smartphone or from a conventional landline phone that is connected to a VoIP adapter. [Voice over Internet Protocol (VoIP)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) ### 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. Nowadays, phone technology is evolving away from ISDN and towards IP telephony via [Voice over IP (VoIP).](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) [Integrated Services Digital Network (ISDN)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/isdn) ### Virtual fax machine With [Cloudya](https://web-production.nfon.com/gb/products/cloudya), you can send and receive faxes. • Reach each employee directly via a personal fax number • Share virtual fax machines with a user group • Receive faxes in PDF format by email • T.38 fax protocol supported • Connect analogue fax devices via auto-provisioned analogue adapter Want to know more? [Check our leaflets](https://www.nfon.com/en/service/documentation/manuals/fax)! 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