When I try to couple the BH-218 to my Garmin i press the ]as in the manual but only get voive prompt on or off, the coupling mode does not seem to function.
My guess is you don't have the headset in pairing mode. The instructions below are from the instructions for the BH-218"
Before using the headset, you must pair and connect it to a compatible phone.
1. Make sure your headset is switched off and your compatible phone is on.
2. If you've never paired the headset with a device, or you've cleared the pairings,
switch the headset on.
If you've previously paired your headset with another device, press and hold the multifunction button
for 5 seconds.
Pairing mode is switched on, and a blue indicator light starts to flash quickly.
3. Within 3 minutes, switch Bluetooth on in your phone, then set it to search for
Bluetooth devices. For details, see the user guide of the phone.
4. On your phone, select the headset from the list of found devices.
5. If asked, type in the passcode 0000.
When the headset is connected to a phone, the Bluetooth indicator light flashes
You can pair your headset with 8 phones, but you can only connect it to 2 phones at
the same time.
With some phones, you may need to make the connection separately after pairing.
Tip: Can't connect the headset to a compatible phone? Make sure that the headset
is charged, switched on, and paired with the phone.