Teldok rapport 41 - Digitalisering i förbundsrepubliken

56 DIGITALISERING I FÖRBUNDSREPUBLIKEN
voice services with the related consequences and expectations for all network
components concerned.
• This could result in the production of a larger number of items particularly in the
field of terminals at relatively low manufacturing costs. Furthermore, it will be
possible to reduce the unnecessary variety of terminals by streamlining the
number of different types.
• The ISDN involves a number of system-related and technological (i e component-related)
challenges for the manufacturers which are certainly not free of
risks but on the other hand will also be able to fulfil high expectations.
ADVANTAGES FOR THE PTTs
• The digitalisation of the telephone network is in itself independent of any ISDN
implications - an economically useful measure, the advantages of which are outlined
below:
considerable savings in space owing to microelectronics;
price reductions or equality of prices with a sometimes considerable increase
in effidency;
the prices of digital systems will continuw to fall while the prices for analogue
systems will remain almost the same:
noticeably lower operating costs;
higher quality of service, higher efficiency.
• Additionally, the concentional analogue or electromechanical technology will no
longer be able to meet inte increased requirements in future.
• The simultaneous use of several telecommunication networks for different
applications usually involves extra cost for the development, technology,
planning and operation of the different networks and their components, which
are considerable in some cases particularly as far as switching systems and the
subscriber line including signalling are concemed.
• Avoidance of separate networks for different services.
• It is a logical consequence of the basic dedsion to digitalise the telephone network
for economic reasons to digitalise the existing subscriber lines of the digital
telephone network as well, thus making the decisive step towards the ISDN. As
the copper pairs of the subscriber lines represent by far the largest portion of the
investments made in the telecommunication network up to now, it seems logical
to modernise, i e digitalise them and thus make multiple use of them.
• Economical use of the equipment of the digitahsed telephone network, especially
the copper pair of the subscriber line.
• The ISDN will offer new and improved services and service attributes within a
relatively short time and at low extra costs.
• Handling of several services over a single access with a single directory number.
• The expansion of the ISDN in line with demand is supported by the modular
design of the digital local exchanges (according to the building block concept).
• The ISDN can also be expanded by integrating broadband services.
To sum up. the ISDN may practically be regarded as a by-product of the digitalisation
of the telephone network requiring only little extra expense since the most
important and costly components of the ISDN are already available in the digitalised
telephone network. The standard bit rate of 6 ' .:bii/s in the ISDN furthermore
allows to implement all the essential telecommunication services in a single and
highly efficient digital communication network.