NEC univerge sv8100 Installation Manual page 18

Select 'Register' on the Service Setting screen and click next.
Now choose either Multi line mode, Single Line Mode or Multi line mode and Phone
advanced mode (For only UCB.) Multi and Single line are different modes in which TAPI
applications can use the TAPI service. You should choose which ever mode the application
you are using supports. If products such as Desktop Suite Attendant or MyCalls are to be
used this must be Multi-line mode. For UCB installations select Multi line mode and Phone
advanced mode (For only UCB) and click next.