ISDN FAQ

This FAQ gives the answer to the most frequently asked questions concerning the ISDN service at NTNU. If you have any comments or additional information, please let us know.

1. What is ISDN

ISDN, which is short for "Integrated Services Digital Network", is a telecommunication service. Through a regular telephone subscription you get one phone line, but with the use of ISDN technology you can get several channels on the same line. ISDN Basic gives you access to three channels, two high-speed channels and one channel with lower speed. For the majority of users, the channels of interest are the two high-speed channels. These two channels can be used simultaneously for different tasks. The third channel can be used parallel with the two others, e.g. for data transfer. An ISDN Basic subscription gives you the the opportunity to use two different telecommunication services simultaneously. You get two separate telephone numbers, and can have two active telephone conversations at the same time. If someone tries to contact you while both lines are occupied, they will get a number-unobtainable tone. An ISDN Basic prescription is cheaper and of higher quality than two regular telephone subscription.

2. How do I order an ISDN subscription

To order an ISDN subscription through Telenor, you can call the the number 05000. For more information, go to the Telenor webpage.

3. What is the number to NTNUs ISDN service?

The telephone number to NTNU's Cisco router is 73 55 00 00. This is the number your ISDN card should contact in order to log on to the ISDN services of NTNU.

4. What are the traffic rates

You are referred to Telenors price list for updated prices on Telenors services. Note that if you cross-link the two B-lines of the ISDN card, the prices will double.

5. Is this service available for SINTEF employees?

No, the ISDN-dialup service is only available for NTNU students and employees. SINTEF-employees must use SINTEF-s dial-up service. Contact SINTEF for more information.

6. How much does it cost to move my subscription

You are referred to Telenors price list for updated prices on Telenor subscriptions.

7. What operating system is the ISDN software meant for?

We recommend purchasing the Eicon ISDN card. This card is shipped with software for all Windows versions and many other operating systems. For help on configuring your system in order to use the dial-up ISDN service, see . ( Only in Norwegian )

8. Can old analogue telephones still be used for conversations?

Yes, but you will have to use a terminal adapter (TA). This can be purchased at a Telenor distributor. Using a TA also enables you to use an analogue modem on the ISDN line.

9. Will it be possible to stay online all the time?

The software supports many different connection options. One possibility is to enable the card to automatically log off after a certain period of time if no data is transferred (typically after 180 seconds). If you click a link, the card will reconnect and load the page. This gives you the impression of being continously online. You can also control the connection manually, and log off whenever you want to.

10. Can two computers use the same ISDN subscription?

Yes! The easiest way to do this is to use a ISDN router.
Alternatively, you can use computer running Linux as router. This is a cheaper solution, but is quite complex technically.
It is also possible to connect two PCs directly to separate ports on the NT1 box. Each PC will then occupy one B channel each, as opposed to using a router, when both PCs would share a channel.
For windows, there is a software based solution called Wingate. A computer with this program installed can manage connections from several other computers through one ISDN connection.

11. What connection speeds can I achieve

The ISDN-line consists of two B-channels, each with a maximal connection speed of 64 Kbit/s. A dual connection can therefore achieve connection speeds up to 128 Kbit/s.
The dialup service supports multilinks, but using this option will block your ISDN line for incoming telephone calls.

12. Can the ISDN card be used as a regular modem?

Yes, but the quality of modem support varies. Most cards "emulate" a modem signal using software, which gives a poorer result than by using a real modem. If you need to have modem support on your computer, the best thing would be to buy a combined ISDN/modem-card.

13. Is it possible to make two phone-calls at the same time on an ISDN line?

Yes!

14. How many channels does NTNU offer?

NTNU offers 60 Incoming channels.

15. What is Eurofile

Eurofile is an ISDN standard for file transfer. The method is based on direct peer-to-peer connection between two computers with ISDN capabilities.
NTNU dialup service does not support transfer using Eurofile.

16. How many phones can I connect to the NT1 box?

Maximum three modern telephones or one old fashion telephone can be connected to the analogue channel. Too many telephones connected at the same time can result in a voltage drop, which again might result in loss of calling signal i.a.

17. How do I access my NTNU "home directory" from my personal computer?

This is explained on the page

18. Where can I get help with installation of my ISDN card?

You can only get help with this if you are able to take your computer with you to Orakeltjenesten.

19. Can I pay for data traffic with my MSN-number?

Yes, this is possible. You can configure your ISDN software to use another phone number than the main number. The procedure for this setup varies between software types.

20. What is the CAPI driver?

The CAPI driver is responsible for managing Windows access to the ISDN card.
When a program wants to access the ISDN card, it sends a series of commands to the card. CAPI is the generic term for these commands. Without CAPI, the programs would not know how to communicate with the ISDN card. Each ISDN card has a different set of CAPI, and can therefore not be used by a card from another supplier.
CAPI is the foundation of the communication between Windows and the ISDN card. In addition, you have NDIS drivers and the TCP/IP protocol. On top of this you have the various communication programs, such as e-mail and web browsers.

21. What is Microsoft ISDN accelerator pack?

Microsoft ISDN accelerator pack is a update for Win95 which makes the ISDN channels available as modem in External logon. In addition, you will have to install the miniport driver in order to create a link between the ISDN channels and the ISDN card. Microsoft ISDN accelerator pack is an update you need in Windows 95 to ensure that the ISDN-channels will be available. The miniport-driver also needs to be installed to enable connection between the card and the ISDN-channels.

22. What is the miniport driver?

The miniport drivers tricks the External logon program into believing that the ISDN card is a network card, and not a modem. This is neccecary, because External logon can not communicate with the card if it believes it is a modem.

23. Why do I get the "Line is Busy" message?

The error message Line is Busy might result from cable breaks, IRQ conflicts or erronous installation of the miniport drivers. To fix the error, try some of the tips below.

• Check that the cable is connected correctly, both in the computer and the NT box.
• Check for IRQ conflicts
• Reinstall the miniport drivers.

24. How do I connect two B channels into one connection (multi-link)?

NTNU's dial-up service supports multi-link connections. This means that you can bundle two or multiple B channels into one connection for increased bandwith during data transfer.
If you link the two B channels of your ISDN card and use these for data transfer, your telephone number will not be reachable for incoming conversations. Also, using both B channels at the same time means doubling the costs, since you then pay for two active connections at the same time.