Switch Types

National ISDN 1 (Most ISDN providers)

National ISDN 2 (Newer phone technology not in common use at this time.)

AT&T 5ESS (Developed by Lucent technologies paved the way for modern phone switches and still used in Europe.)

ISDN Concepts

S Interface is a single B channel ISDN phone jack. (U interface).The interface between the ISDN BRI line and the NT1. This can be considered the ISDN "phone jack" in the USA & Canada and is frequently in the form of a RJ-11 or RJ-45 type telephone jack. A regular phone will plug into a ISDN phone jack. ISDN has a electrical charge and will damage analog equipment.

One B channel is a Bearer Channel. One of the multiple user channels on an ISDN circuit. Used to carry user's data;. ISDN Basic Rate Interface. The common form of ISDN with 2 Bearer Channels and one D ChanneL. The D channel is typically used as the control channel for the line. This line can assist in pulling up and dropping phone lines for a multilink PPP connection.(128k).

A PRI is a T1 basicly this is 24 channels including the D channel. Most Internet service providers have multiple PRIs or maybe a t3 and racks of isdn terminal adapters for users to dial up and connect to. Primary Rate Interface. A form of ISDN with 23 "B Channels" and one "D channel

SpidS (Service Profile IDentifier) For National ISDN 1 this will be a 14 digit number. The Ten digit phone numbers followed by 0101 in most cases. 1111 or any combination of 1s and 0s might also be valid for National ISDN 1. For AT&T5ESS this will in most cases be 12 numbers they tend to start with 01 then the full number. PIDS The two ten digit phone numbers do not include the 1.

Multilink PPP Both channel bound together as one connection. Singlelink One channel for internet one can be used for standard phone service at all times. IDSL all three channels permanately bond together for a 144kbps connection. In most cases It will not be able to pick up or drop channels when the control channel is in use.

Some ISDN terminal adapters act like routers, some hook up via USB, there are internal modems and serial port modems. Routers will have software to set them up in most cases through a graphical user interface. Set the switch type enter the spids and phone numbers. USB ISDN terminal adapters will most likey install as a local modem and should also come with software.

AT Commands

Terminal adapters in most cases respond to standard modem at commands. You can configure a terminal adapter through hyperterminal using at commands. Most ISDN terminal adapters will probably be based off of the hayes compatible at command set. So at? will hopefully show a list of commands. For the courier 3com/USR ISDN terminal adapters the commands to setup the adapter follow.

For information on how to start a hyperterminal session click link. link

ate1 for echo on to see what you are typing

at*p0=ten digit phone number

at*p1=second ten digit phone number

at*s0=1st spid

at*s1=second spid

at*w=2 for national isdn 1

at&w to save

atz! for the reset

in some case it may be p1 p2 s1 s2 instead of starting with zero. Plus in a lot of cases the customer will have them backwards so you will have to switch them around to stop the irratic behavior.

For multilink PPP the command is ats68=64s69=2&w or at*v2=5*d0=1*p=3s68=64&w it will either be *p or *ppp . If you get into trouble at*? . For unkown ISDN terminal adapters that have to be configured through at commands. at? at*? may be enough to get us started.