10.20.2.1. Adding NV Services to the Functional Bus 
The services can only be assigned to a particular call number that
already exists for example, functional services with OPT=SVC (the result
remains an FBUS).
Figure 100. Functional bus (expansion example)
ADD-SBCSU:STNO=300,OPT=SVC,DVCFIG=DTE,DPROT=SBDSS1;
IMPORTANT:
If there are MSN call number configured
at the FBUS, the new service is automatically added to their scope of
service (see "EURO ISDN Terminals", Section
120.2.1, "Multiple Subscriber Numbers (MSN) on the S0 Bus".