Ble. How to set discoverable mode for fenix?

Not to force it.

But if you look at the Nordicthingy52 sample, in the ble delegate, in the contains function, you can display the devices that are seen in a scan and you'll see some things.

Consider adding a println like this:

    //used to compare UUIDs while scanning  	               
    private function contains( iter, obj ) {
        for( var uuid = iter.next(); uuid != null; uuid = iter.next() ) {
Sys.println("uuid="+uuid);                   
            if( uuid.equals( obj ) ) {
                return true;
            }
        }
        return false;
    } 

If you use something like nRF Connect on a phone, you can also see what's advertising.  I see a watch that isn't paired to the phone scanning, but if it is paired to the phone, it shows as "bonded"

Thank you for your reply.  I'm trying to compile Nordicthingy52 sample and it's not working on my watch. Should it works on fenix5? Where I can find list of compatible devices?

The f5 ia not compatible with CIQ ble.  You can look here: https://developer.garmin.com/connect-iq/compatible-devices/

and click on the blue circle and see if a device supports

• Generic Bluetooth Low Energy Channel

For example, the fenix 5 plus.