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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") ### IP-Centrex [The distinguishing feature of "hosted PBX"](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/ip-centrex#section-3) # IP-Centrex In English, this technology is often translated as "virtual PBX". Even today, in many IT departments terms such as "IP Centrex" are still foreign words. One synonym in current use is "[hosted PBX](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/hosted-pbx)" ("Private Branch Exchange") or "IP Centrex". In contrast to a traditional telephone system, which is operated within the premises of the business using it, this new dimension of the telephone system is centralised and available as a web application. This kind of highly innovative [telephone system](/gb/gb/products/cloudya) also connects to the traditional telephone network, the only difference being that the connection between the telephones and the telephone system equipment is not a telephone cable, but an Internet connection. This means you can connect to your central telephone system from anywhere in the world via a wide variety of devices - from the classic corded phone, to [DECT](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/dect) phones and laptops or desktop PCs with softphones and headsets, through to a mobile phone. Nconnect from NFON customers can also connect via a high-performance symmetrical internet connection ([SDSL or SHDSL](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/sdsl-shdsl)) at a uniquely favourable price. Telephone systems from NFON are based solely on this new, highly innovative technology. The system facility itself is hosted on powerful servers in several geographically separated, highly redundant data centres. With NFON technology, small and medium-sized businesses get access to all the features of a highly professional telephone system. You benefit from a functionality that was previously found only in expensive enterprise solutions and gain the possibility of adding extensions with just a few clicks, with unheard-of scalability and considerable cost savings. The wide range of services available includes features such as voicemail, queueing, voice applications and telephone conference calls. Telephone calls are digitized by the IP phones in [ISDN](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/isdn) quality. The system telephones communicate with the telephone system in data centres via the local company Ethernet network and broadband data line ([ADSL](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/adsl) or SDSL). The servers in the data centre then make the collection to the public telephone network. ### The distinguishing feature of "hosted PBX" It is important to distinguish between solutions that are dedicated outsourced systems for a single customer alone and shared platforms (i.e. a true cloud application). In the first case a provider operates a single outsourced telephone system for a single customer. Here, the cost-saving opportunities are limited by the nature of the offer. With NFON, all customers are provided with one and the same telephone system, meaning that even small businesses can use the full range of functions that a high-end PBX offers, just the same as the large corporations that have already switched to NFON. Of course, for data security reasons, customer records are kept strictly separate. ### Related Articles ### Hosted PBX For a long time now, conventional telephone systems - often also referred to as [PBX (Private Branch Exchange)](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/voice-over-ip) - have belonged to the standard equipment of every company. This is a hardware-based system, which controls communication between the public telephone network and the internal telephone network. This technology now appears to be outdated and is being increasingly replaced by the Hosted PBX system. [Hosted PBX](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/hosted-pbx) ### DECT Digital Enhanced Cordless Telecommunications, abbreviated to DECT, is the name of a standard for the wireless transmission of telephone calls or data. DECT is often used for cordless telephony in buildings and has established a strong presence in this market. A cordless phone with this standard usually consists of a DECT base station and one or more handsets. The DECT base station is connected to the network by an analogue or digital phone line. It handles the radio part of the phone connectionand voice transmission with the handsets. Systems using the Digital Enhanced Cordless Telecommunications standard allow a single base station to support up to 6 cordless handsets. The frequency range uses various radio bands at around the 2 GHz range. A handset can be used at distances of up to 50 metres indoors and up to 300 metres in an open environment and reach standard data rates of 32 kilobits per second. The maximum transmission power of the base station is limited, so that coverage over any greater distance can only be achieved with booster units. In order to be used, a handset must first be authenticated by a base station. In general, this is accomplished by using a special PIN, set by the user. The DECT standard can also provide the encrypted transfer of user data, thereby protecting it from unauthorised access. However, this type of transmission is relatively rarely used and is not implemented in many phones. In order to reduce so-called electric smog there are various methods used within Digital Enhanced Cordless Telecommunications to minimise the transmitting power of both the base station and the handset while in idle mode. These methods are often called ECO DECT. Want to know more? [Check our leaflets](https://www.nfon.com/en/service/documentation/manuals/dect-phones)! [DECT](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/dect) ### SDSL / SHDSL **What is SDSL and SHDSL?** The terms Symmetric Digital Subscriber Line (SDSL) and Single-Pair High-Speed Digital Subscriber Line (SHDSL) mean the same thing. They refer to a specific type of internet connection where the same bandwidth is given to both uploads and downloads. Note: The two different names exist because two separate organisations introduced their own standards for this technology. The SDSL standard was approved by the European Telecommunications Standards Institute (ETSI), and SDSL was approved by the International Telecommunication Union (ITU). [SDSL / SHDSL](/gb/get-started/cloud-telephony/lexicon/knowledge-base-detail/sdsl-shdsl) ### Asymmetric Digital Subscriber Line (ADSL) The acronym ADSL stands for the technical term Asymmetric Digital Subscriber Line and refers to a standard frequently used for the broadband Internet access system DSL. ADSL allows copper twin wire, conventionally used for telephony, to transmit data with a high bandwidth. The transfer rates for upload and download are asymmetrical and reflect the common usage of Internet consumers. The download rate is a multiple of the upload rate. With increasing signal loss in copper wire at high frequencies, the maximum transfer rate is highly dependent on the distance from the user to the local exchange. The remote terminal of the ADSL connection and the ADSL modem or router is formed by the DSLAM (Digital Subscriber Line Access Multiplexer) of the network operator. It handles a number of ADSL connections and is operated as an indoor DSLAM at the central exchange or as an outdoor DSLAM in a street cabinet or at any other central point. 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