ISDN is available in either ISDN 2e or ISDN 30. Format for the UK is EuroISDN (DSS1)
Microsoft CAPI only supports one manufacturer/driver, therefore multiple ISDN cards must share the same chipset and driver.
MSN - Point to Multipoint DDI - Point to Point
NOTE 90% of installs will be DDI, but the default is set to Point to Multipoint.
NOTE Same Telephone number on everybox, then DDI or PtP. Different Telephone number of every box, then MSN or PtMP.