Differing national ISDN standards

ISDN equipment that works in one country might not work correctly when installed in another country because of different national standards regarding:

voice encoding

-law encoding is used in North America and Japan for digital-analog conversion, while A-law encoding is used elsewhere. Some devices provide switches for selecting an encoding type; if not, your device must use the local encoding standard.

communication between terminal equipment and the telephone exchange

Interoperability of equipment and services varies greatly because of the variety of services, which services are available from a local ISDN provider, and how regulations are interpreted. Check with your local service provider to ensure that your device's functionality is supported.

telephone equipment regulation

Equipment approved for use in one country is not necessarily approved elsewhere. Check with your local ISDN provider to ensure that your device is supported on their ISDN network.

who provides ISDN equipment

North American customers are expected to provide their own network termination devices, while elsewhere they are supplied by the local ISDN provider. Consumer ISDN devices may thus have different physical connectors depending on the area where they are intended for use.