You can get half the answer without a SMH-10. Trying Bluetooth pairing your Zumo 665 and Evo 4G if that works you are over half way there. The recommend pairing to is a "star" pattern off the Zumo. So the next step is to pair the SMH-10 with the Zumo. I have the "Sena SMH-10 Bluetooth Headset Version 2.0" and a Zumo 660 paired without any problems. Of note is that the "SHM-10 v2.0" can have software updates performed by the owner after purchase. I had the "3.0" software as shipped and I have just applied the "3.2" software. Both worked with the Zumo 660 at its latest software version. If you have the earlier non "2.0" version of the Zumo, I do not know if there are any issues.
1 year, 6 months ago