[Solved] Brain2 + R-XSR F-Port no signal on any channel

Why did you select the UNINVERTED protocol (0V = 0, 3.3V = 1)?
The standard output of FrSky receivers is INVERTED (0V = 1, 3.3V = 0) like the Futaba S.Bus / S.Bus2 protocol.

We took an R-XSR receiver and loaded the "RXSR_ACCST_2.1.1_Fport_LBT" firmware into it (LBT because we are in Europe).
We connected the R-XSR receiver to the CH3 port of a standard Brain2 control unit with the latest firmware 3.4.086.
We connected the flight control unit via usb to a PC and through the software interface we selected the standard "F.Port / F.Port2 INVERTED" icon on page 3 of the Wizard.
We then powered the flight control unit by means of a 4S NiMh battery connected to any of the servo connectors in order to also power the receiver.
We binded the R-XSR receiver to a RadioMaster TX16S transmitter (already previously configured for RC eli) with multimodule updated to "V1.3.3.7 AETR" in which we had selected for the multifrequency module the FrSkyX2 and LBT(EU) RF protocol following the usual FrSky Bind procedure.
Then we went to panel 5 of the wizard and by moving the sticks of the transmitter we see the sliders of the various radio channels move regularly.

I meant to say INVERTED, this is what I have selected.

I found the issue: if you long press bind button on R-XSR while it powered on then blue led of the receiver stops and receiver gives no output (seems to be a feature of the receiver).
I accidentally did this while I was binding the receiver thus had the issue.

It can be reverted by long pressing bind button again and blue led comes on again. all good now

thanks for the reply.

Binding procedures between transmitters and receivers are explained in the respective manufacturers' instructions and have nothing to do with our flight control units.
However, we are glad that the problem has been solved.