Hi guys. First thank everybody for helping me those previous week. I'm really stuck on something now that I can't understand: When I' using the file source in OP25.grc everything seems working perfectly, I got the 4 ligns in the Dibits and I can hear someone speaking. HOWEVER when I use my USRP B100 here is the situation: I have 4 perfect lignes but NO AUDIO. Moving from the File source to the USRP, I dont touch any audio sink frequency or interpolation of the Rational Resampler or Channel rate so logicaly the probleme should not be coming from here.. Im pretty sure that I applied the patch r307. Furthermore this patch is also to make the audio work wich is the case with the file source so what..? Any suggestions please? Why the audio is working with the files source but not with the USRP? Thank you very much Souf