-       /* Read bytes from the USB OUT endpoint into the UART transmit buffer */
-       int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
-       if (!(ReceivedByte < 0) && !(RingBuffer_IsFull(&USBtoUART_Buffer)))
-         RingBuffer_Insert(&USBtoUART_Buffer, ReceivedByte);
+       /* Only try to read in bytes from the CDC interface if the transmit buffer is not full */
+       if (!(RingBuffer_IsFull(&USBtoUART_Buffer)))
+       {
+               int16_t ReceivedByte = CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
+
+               /* Read bytes from the USB OUT endpoint into the UART transmit buffer */
+               if (!(ReceivedByte < 0))
+                 RingBuffer_Insert(&USBtoUART_Buffer, ReceivedByte);
+       }