When using the X108G connected to a Smart phone - such as when using the PocketRXTX An-Droid App to control and display the X108G settings the receive noise level can be drastically raised by EMI from the smart phone. I have tried screened cables clip-on ferrites and winding the USB cable through a Ferrite core. None of these actions work as the interference is being passed down the wires within the USB cable. I am glad to report that I have come across a board meant for reducing EMI getting into Audio DAC equipment which works with the X108G link, drastically reducing the level of additional noise. It is available out of China via eBay - this is the posting on eBay.de - use the ID number on your local eBay site to get the text and price in your language: USB EMI Noise Suppressor Filter USB Signal Purifier for USB DAC Audio Device | eBay Please note, there are two connectors on this board. An USB-A standard socket which takes the cable from the phone - so the other end of the cable has to be Micro-usb or USB type C depending upon how new your phone is AND the plug that goes into your phone has to have "on the Go" OTG enabled, so that the phgone acts as a host while the X108G is the client. The second connector looks like a Micro-USB socket in the picture but in fact is a mini-USB socket so the cable from this side to the X108G has to be a Mini-USB to Micro-USB cable with male plugs on each end. I hope this information helps others who experience EMI coming into the X108G via it's USB CAT control connector.