Connecting an ISDN with Linux
If you are still using ISDN, you will find this helpful… ISDN used to be the fastest connection, compared to regular analog modems. Its functionality is still the same (Very expensive by the way). That is the reasons not a lot of users have them. But of course ISDN was an alternative to T1, T2 and T3. Today ISDN is being replaced by DSL which is actually more cost effective. DSL is still slow compared to T lines. But I am very sure that with DSL you can run any server. Trust me I already run several servers on the same DSL line and everything runs smooth. You can always upgrade to T lines if you think you have the need or money. The ISDN modems have to be operational just like the regular modem in order to make a successful connection. If you have noticed earlier during the wizard, you had the option to select your connection type. Well that's exactly the way to do it. Get back to the control center and run the wizard.
Click on Network & internet Click on connection Click on wizard Click on expert This time click on ISDN
Fig. 2.26
Click on Next
Fig. 2.27
Pay attention when you select your modem type, this decision may cause your success or failure. Remember external modems usually are assigned to COM1 and COM2 respectively
Once you have selected your modem type, you have to select the appropriate COM port. Look at figure 2.28 it describes all the COM ports available; if the modem is internal it could be connected to any of the ports from com3 to com8. In this scenario the modem is connected to com2, which is an external modem. An ISDN modem is a dial up modem, and it requires all the necessary information to accomplish the authentication. Fill out all the information on panel fig. 2.29. Fig. 2.28
Fig. 2.29 An ISDN connection is assigned a dynamic IP address. That is the reason DNS is optional here, because everything is DHCP (there may be special occasions when ISDN is using static IP). Fill out the necessary information and click next. You will be prompted to finish and apply the setting. After applying the setting, you should be able to connect. Enjoy!