The distinction between items of equipment intended for either the European
or North American markets is often included in their product designation, such
as "S/T type" for EuroISDN, or as "U interface" for the
North American type of equipment.
A European traveling to the United States and intending to use their S/T-type
ISDN equipment would need to purchase the appropriate NT1 to connect to the
local provider's U interface.
In addition to these physical differences, the protocols used in different
countries can vary. It may be necessary to select a different country setting
for the switch type in use by the local ISDN supplier. Check with the supplier
and use the DIVA setup program to make the appropriate changes if required.