If you're changing your system, think about connecting the right telephone lines first. Not just in terms of what you need, but regarding the logistics. If you're moving, make sure that you plan well in advance. If you need help, just call us on 0800 970 9751 and we can start you off on the right track.
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Analogue LinesOnce upon a time only analogue lines could be connected to telephone systems and they could be very expensive too if analogue Direct Dialling In was needed. It meant that a business needed to install one physical copper telephone line for ever 
DDI number required.
Now that has changed as explained below under ISDN, however, there is still a small demand for analogue lines.
Copper telephone lines are predominately used residentially and the numbers are reducing in businesses. Smaller companies who have no need for additional functionality continue to use analogue lines and this can still be cost effective. However, typically these are for line quantities below eight. Above eight lines the cost can be justified to change to ISDN. ADSL (broadband), single fax lines, modems, alarm systems and legacy private lines are the most common use for analogue lines. In days gone by, it was an Oftel requirement that all telephones systems be fitted with a powerfail fall-back facility whereby, irrespective of the type of telephone lines connected to the system, 20% of the line capacity needed to be available in the event of a power cut. This is no longer a requirement, however, with larger organisations it is worthwhile checking to make sure that there are no rogue telephone lines that are still being paid for, even though they are not being used.
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ISDN (Integrated Services Digital Network)
ISDN has been available for over 20 years and is provided in the form of ISDN2e ( BRI) and ISDN30e (PRI). Originally there were three predominant benefits of ISDN - speed, quality and integration. Transmission of data was in the region of 26 times faster than a normal analogue telephone line and, as the digital technology it was less susceptible to electromagnetic distortion, quality and accuracy were superior. Regarding integration, the main advantage with digital communications was that voice, data and images could be transmitted on a single network. This reduced the number of different networks was necessary to subscribe to.
As you will read, the transmission of data over broadband has now become commonplace and not as originally anticipated over ISDN.
ISDN2e
Once ISDN2e became widely available it had a significant impact on the telecoms market as it effectively doubled the capacity of the copper lines in the ground, i.e. two connections via one copper wire.
ISDN2e has given businesses the ability to connect a low number of telephone lines economically (typically no more than 8 at a single site) and at the same time providing a higher level of functionality. ISDN2e provided multiple subscriber numbering, MSN, which meant that an ISDN2e circuit could have more than one number attributed to it. This is more widely known now as DDI.
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ISDN30e
ISDN30e, as the number suggests, relates to the number of voice channels or lines, i.e. 30, available on one circuit (single fibre optic cable). If more than 30 lines are required multiple circuits can be connected to a single telephone system and calls are made and received across all channels. The minimum order quantity provided by British Telecom is eight channels at a single installation: smaller installations would be recommended to install ISDN2 with the same functionality.
In addition to the 30 channels for voice, two further channels are used for data and synchronisation. It is via the data and synchronisation channels that additional functionality is achieved.
Direct dialling inwards (DDI) is available across ISDN30e circuits and is now commonplace throughout the UK in most businesses. The main advantage of DDI is that telephone calls can be received by individual members of staff thereby reducing the number of calls answered by a receptionist.
In addition to multiple telephone numbers, ISDN also enables important technical features, such as calling line identity ( CLI) which enables users to see the telephone number of the person calling. In conjunction with CLI and the data channel, it is possible to harness the functionality of computer software to control telephone calls. In simple terms it is now possible to make and receive calls via database packages such as Outlook, Goldmine, Act! and Salesforce. See CTI section for more information.
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If you are not sure which ISDN service would best suit your business please contact us on 0800 970 9751 or email us at This e-mail address is being protected from spambots. You need JavaScript enabled to view it
