IsBtDevicePaired

function OnStart()
{
    app.ShowProgress( "enabling Bluetooth" );
    app.SetBluetoothEnabled( true );
    while( !app.IsBluetoothOn() ) app.Wait( 0.2 );
    app.HideProgress();

    if( devices.length )
    {
        paired = app.IsBtDevicePaired( devices[0].name );
        app.Alert( paired, devices[0].name + " paired" );
    } else
        app.ShowPopup( "No Paired devices found" );
}
<sample>

<sample Check Paired from Available>
function OnStart()
{
    app.ShowProgress( "enabling Bluetooth" );
    app.SetBluetoothEnabled( true );
    while( !app.IsBluetoothOn() ) app.Wait( 0.2 );
    app.HideProgress();

    app.DiscoverBtDevices( "", bt_OnFound, bt_OnComplete );
    app.ShowProgress( "Discovering bt devices" );
}

function bt_OnFound( name, address )
{
    var paired = app.IsBtDevicePaired( name );
    app.ShowPopup( name + ": paired: " + paired );
}

function bt_OnComplete() {
    app.HideProgress();
}

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function OnStart()
{
    app.ShowProgress( "enabling Bluetooth" );
    app.SetBluetoothEnabled( true );
    while( !app.IsBluetoothOn() ) app.Wait( 0.2 );
    app.HideProgress();

    app.DiscoverBtDevices( "", bt_OnFound, bt_OnComplete );
    app.ShowProgress( "Discovering bt devices" );

    lay = app.CreateLayout( "linear" );

    lst = app.CreateList( "", 1, 1, "fontawesome" );
    lst.SetOnTouch( pair );
    lay.AddChild( lst );

    app.AddLayout( lay );
}

function bt_OnFound( name, address )
{
    var image = "";
    if( app.IsBtDevicePaired( name )) image = "[fa-bluetooth]";
    lst.AddItem( name, address, image );
}

function bt_OnComplete() {
    app.HideProgress();
}

function pair( name, address )
{
    if(!app.IsBtDevicePaired( name ))
    {
        app.ShowProgress( "Pairing " + name );
        app.PairBtDevice( address, OnPair );
        lst.SetItem( name, name, address, "");
    }
    else
    {
        app.ShowProgress( "Unpairing " + name );
        app.UnpairBtDevice( address, OnUnpair );
        lst.SetItem( name, name, address, "");
    }
}

function OnPair( name, address ) {
    app.Alert( name + " " + address, "Pairing successful!" );
}

function OnUnpair() {
    app.Alert( name + " " + address, "Unpairing successful!" );
}

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