Internet acces via ISDN by Ralf Gall 
Where to go:
56k modem
cable TV
home of the seminar

Discussion ISDN is the high-speed access technology of choice for home users and small to medium businesses. Nothing else is as widely available, economical, or mature. The hardware, lines, and Internet access are all available today, and millions of people are already taking advantage of it. ISDN is already an ITU standard, so there's no need to fret over looming standards wars or patent lawsuits.

One huge advantage of ISDN is that one ISDN line has two phone lines with two phone numbers. You can surf and use the phone at the same time. Practically all consumer ISDN hardware has a port for plugging in analog phone equipment (telephones, fax machines, etc.) so you can use your analog equipment over the digital line. You can even plug your modem in for calling services that don't support ISDN.


Speed Consumer ISDN has two 64K bearer (B) channels and one 16K delta (D) channel that acts as a controller. You can use one or both B channels for surfing, for speeds of 64K or 128K (in some areas, the speeds are 56 and 112). Because the lines are digital, there is very little noise, and you're assured of getting a connection at the full speed.

So, ISDN is faster then the 56k-technology and much more resistant against disturbance and failures. ISDN is standardized world wide and accepted by the greatest part of the Internet providers. Read more about the technology and the historoy in the chapter about ADSL. 


  • No problems because of interferences
  • Max. download speed 64 kbps;  using both lines 128 kbps
  • Max. upload speed 64 kbps; using both lines 128 kbps
  • Supported by all the providers
  • Proved technology
  • Two phone lines

  • An ISDN connection has to be installed
  • An ISDN adapter is necessary