Motorola HS850 Manual page 24

pair to more than eight devices is made,
the oldest paired device is removed
from the list.
Any of the eight paired devices can
initiate a paired connection to the
headset.
The headset will only automatically
initiate a paired connection (via opening
the boom) with the last device it was
connected to. If you want to connect
the headset to another device in the
paired device list, you must initiate the
connection from that device. Whichever
of the eight devices initiates a
connection to the headset afterwards,
that device then becomes the "last
connected" device.
22 Using Your Headset