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I have a friend who wants to set his business up using an ISDN connection for the internet. Is an ISDN router and a hub all that is needed or is an ISDN modem also needed? How would he have to set this up?

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isdn setup

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An ISDN router includes all of the modem circuitry needed to talk to the ISDN line.

When you use an ISDN router, such as a 3com OfficeConnect, the router handles all communication with the ISDN line. Your machines connect to the router using TCP/IP, using either the router’s built-in hub or an external hub. The router automatically dials the ISP and logs in when it sees traffic from your LAN to anywhere off of your lan. The router typically provides NAT (network address translation) so thatall of your internal stations funnel through one external IP address, which the router obtains when it dials in.

WARNING WARNING WARNING
You need to make VERY sure that none of your workstations generates any net traffic without intending to. Ifthis happens you can get a very high ISDN phone bill unless you have a flat-rate ISDN connection (rare and becoming more rare). Once the router connects to the ISP, it stays connected until it sees no traffic for a designated amount of time. If you have, for example, a browser open on your desktop pointed at a page that auto-refreshes every few minutes, the router connection may never drop. (I recently saw an ISDN bill showing a local call with 1 initial minute and 8700 additional minutes — ouch!)

By contrast, an ISDN modem is a modem only. It attaches to the serial port of one machine, and the user on that machine uses dial-up networking to dial a number. Except for the drivers loaded and the speed, the ISDN modem behaves exactly as would a 56k modem as far as the computer is concerned.

In general if your friend can get DSL or cable modem, it will typically be better/cheaper/faster than ISDN. In some areas, ISDN is the only high-speed choice.

Good luck.

isdn setup

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The ISDN router is all you will need unless there are many PC’s, then an additional hub will be needed.

All ISDN routers are slightly different, CISCO ones tending to need highly trained specialists to install. A 3-com Officeconnect is quite easy to set up and install. You initially connect it to one workstation and the ISDN line ENSURING THAT YOU HAVE CHANGED THE IP ADDRESS OF PC TO THE SAME IP RANGE AS THE ROUTER (it tells you this in the instructions). There is then an easy front end that lets you put in your ISP details and the phone number of your ISDN line. Once this is up and running you can change the IP address of the router back to the same range as your network, connect it to a floorport, or leave it in the PC (if it is a peer-to-peer network).

As another warning, if you are using it for internet email, the ISDN line is brought up when you send an email and incoming email is downloaded to you at this point. However, if there are quite a few users sending many emails throughout the day it could prove to be costly, especially if also surfing. Keep an eye on the ISDN costs, and consider a leased line if the bills are enormous.

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