How can I add two RFCOMM devices?

Question

I want to connect my PC (running Ubuntu 14.04) to an Arduino Uno via Bluetooth.

I added a RFCOMM device like this (MAC addresses are examples):

rfcomm0 {
    bind yes;
    device 00:00:00:00:00:00;
    channel 1;
    comment "Serial Port 1";
}

in the following file: /etc/bluetooth/rfcomm.conf and it works. Then I wanted to add a second one by appending

rfcomm1 {
    bind yes;
    device 11:11:11:11:11:11;
    channel 2;
    comment "Serial Port 2";
}

but then only rfcomm1 exists and rfcomm0 not anymore.

I followed this tutorial (in German):
https://www.dinotools.de/2014/03/05/raspberry-pi-mit-arduino-per-bluetooth-verbinden/.

How can I do it?

Answer 1

I don't know why but I have to connect both devices (single or together) with channel 1, then it works.