10.20.2.2. Adding MSN Call Numbers to the Functional Bus 
The introduction of MSN call numbers lets you reach functional terminals
at the main number or at a new call number. You can also connect additional
functional terminals for the same services as already configured at the
main number to the bus and reach them at the bus's new call number
(see also "EURO ISDN Terminals", "Section
120.2.1, "Multiple Subscriber Numbers (MSN) on the S0 Bus").
Figure 101. Functional bus with MSN call numbers (expansion example)
Add an MSN call number to the existing functional bus with:
ADD-SBCSU:STNO=301,OPT=MSN,MAINO=300;