respect to subsurface, I have been unpairing and repairing a few times. That is to making sure that my OS forgets the dive computer before I attempt to pair again.At the second time bluetooth conection worked. Thanks to Dirk advice, from Subsurface.
Respect to OSTC Companion. I choose OSTC2. I do not Know if it is correct.OSTC Plus doest not appear in the menu.
If I choose port COM3 Companion show "Error: Port COM3: unable to open port"
If a choose port COM4 Companion show "Connecting ..." and nothing else.