Motorola HF800 Guide De L'utilisateur page 20

Using Your Portable Speaker
Action
Short Press Power Reject a Call (phone rings)
Long Press Power
Note: Phones supporting only the Headset Profile will only recognize
functions associated with the "Short Press MFB" action. For phones
supporting only the Headset Profile, a short press of the MFB may initiate
either a voice dial or a redial of the last dialed number depending upon the
phone's settings.
Note: Phone and service plan must support 3-way calling and call waiting to
utilize the functions associated with these features.
18
Function
Reject Second Incoming Call
End held call
In Call, Add Second Call (creates 3-way call)