14.9.1.2.3. Call Forwarding 
Functionality
The OS4K user can forward calls to an Skype for Business FOR BUSINESS
party. CFA - Call Forward All, CFB (only on OS4K side) - Call Forward
Busy, CFNA - Call Forward No Answer – possible, CO behavior;
- Display Forward Unconditional/Busy – Independent of forward destination
- Calling party will see called name and number on first line display.
- diverted-to party will see calling party name and number on first
line. - no visible indication that a call forwarding happened on any
display.
- Display Forward no reply – Independent of forward destination
- Calling party will see called name and number on first line display.
- diverted-to party will see calling party name and number on first
line. - no visible indication that a call forwarding happened on any
display.
Forward switching is done on both sides.
Restrictions and limitation
Party A doesn’t get forward information. Call forward busy not
supported on Skype for Business side. PBX is not aware of call forwarding. Voice
mail scenarios on OpenScape 4000 side are not possible. Call forward
via rerouting not possible, e.g.call forward from OS4K to Skype for Business
in case of incoming call from Skype for Business will not free resources.