Send data with AT commands(Flutter to Bluetooth-serial)

Question

I have a Bluetooth device with serial port, the idea of the device is read data from a iButton with an adapter connected to the serial port of bluetooth device. The communication only accept 8 bits. I use Flutter with the librarie "flutter_bluetooth_serial" This is the flow that I can communicate with the Bluetooth device.

Flutter code(Write to Bluetooth):

///AT-COMMAND REFERENCE EXAMPLE
///+++
///at+pass=0000
connection!.output
        .add(Uint8List.fromList("<AT-COMMAND>"));
    await connection!.output.allSent;

Flutter code(Read from Bluetooth):

 messages.add(_Message(3, Utf8Decoder().convert(data)));

Communication Flow

1.(The device already paired with my phone device)

2.+++
-Please enter password
3.at+pass=0000
-Remote Configuration Enabled 
4.at+btinfo?
-0001950CA32E,sd1000v2.0.3-oca32e,mode3,pending,0,0,NOFC

OK

5.ato
6.in this time I need send this information [0xf0, 0x11, 0x02, 0xff, 0xff]

The problem is that I don't received any response. Thank your for your answers. Any answer could help me. :D