Multitech MT128ISA-UD User Manual

in their ISDN BRI network and an end-user's four wire terminal equipment. The

NT1 drives an S/T-bus which is usually 4 wires, but in some cases may be 6 or 8

wires.
The name of the S/T bus comes from the letters used in the ISDN specifications to

refer to two reference points, S and T.  Point T refers to the connection between the

NT1 device and customer supplied equipment.  Terminals can connect directly to

NT1 at point T, or there may be a PBX (private branch exchange, i.e. a customer-

owned telephone exchange).  When a PBX is present, point S refers to the connec-

tion between the PBX and the terminal.  Note that in ISDN terminology,

"terminal" can mean any sort of end-user ISDN devices, such as data terminals,

telephones, FAX machines, etc.  The diagram below reflects interface points in a

typical ISDN network.
If your ISDN product operates with a S/T outlet interface, you need an NT1 device

connect to the ISDN switch. MT128ISA-SD/SV adapter needs an NT1 device to

connect to the ISDN switch, but MT128ISA-UD/UV adapter does not require NT1

device. In the UK, and in many European countries, an NT1 device is supplied by

your telephone company.  Therefore the -ST adapters are required for these coun-

tries.

If you want to use an ISDN adapter to connect to the Internet, you must get an

Internet access account from an ISP (Internet Service Provider) in your country.

You must also confirm with your ISP that they support ISDN access (either single

channel 64K or 128K MLP).