Gateway Lite BT11- make sure the files are not write protected (to do so use check the files on a PC)Please note: The write protection cannot be switched off on certain Sony USB. Such USB drives cannotbe used with Gateway Lite or Lite BT.If nothing helps you need to get some details about the USB drive:- Size (we are fine up to 256 GB)- Brand (cheap drives are not always supported due to low quality memory chips on board)- File system (only FAT32 is supported)- Partition: only one (!) partition is supported. Some USB drives come with free backup andother options which use a separate partition, that could cause the recognition failure- Check if an aftermarket extension cable is used- Try the system with another USB device with only a few files on itN. Phone compatibilityWe are constantly working on our compatibility chart, however there are still quite a few untestedmodels. But since our new BT devices have been equipped with the latest BT chip on board, theGateways work fine with most of the phones (e.g. iOS, Android, Blackberry, Bada). There are somevery specific local phones from Verizon or AT&T we were never able to test before. If you have anyfeedback on phones working fine, please share the info (!).The current chart can be downloaded from http://www.dension.com/compatibilityO. Phone issuesThe Gateway Lite BT offers both HFP and A2DP features. Since there is no text option, there will be noinformation on the radio screen upon receiving or making a phone call.Frequently asked questions regarding telephony:- Microphone volume is low: press the next track button during the phone call, letting you tochoose from 10 different volume values (a beep will be audible via the speakers during thevolume setup process). If you find the optimal sound level, you can leave it in that position andit will be saved automatically when the phone connection is severed- Phone does not connect: In rare cases it might be somewhat difficult to pair the phone to theGateway Lite BT device. In such cases, please ask to turn the BT option OFF on the phone,reboot it and try again. If still no luck, please disconnect and reconnect the Gateway Lite BTfrom power. If it did not help, please check if a new firmware is available for the Gateway LiteBT and/or the phone (!). Additionally testing another phone is highly recommended to find outif the problem is related to this specific phone or not- A2DP volume: The volume can be changed similarly to the other sources, like iPod, USB. Thevolume configuration files need to be downloaded from our website to change default settingsusing a USB drive (AUX level has to be increased or decreased)