hello apuva,
the pics you have shown above cable 1 is connect the mobile(your device) to PC(host) via USB… so the procols will be follwed as USB one… now in pic 2 ys have shown USB to serial converter… the USB side must be connced to HOST and the serial DB9 pin on the device side…. you cannot connet it in reverse way…
i never tried but i studied a little bit in USB so i can say that….