I hope following USB to MIDI cable will help you.
Item: Interface PC to Music Converter Cable USB to MIDI keyboard Wire Line
Place: eBay
URL: http://www.ebay.com/itm/MIDI-to-USB-Interface-Cable-Adapter-for-Keyboard-Electronic-Drum-Music-Create-/252468442079?hash=item3ac84ab3df:g:AfsAAOSwIgNXjzaL
But in some case these low cost cables comes without it's important internal components.
And followng link will help you to solve these kind of issues, if you ordered such cable.
http://www.arvydas.co.uk/2013/07/cheap-usb-midi-cable-some-self-assembly-may-be-required/
Incorrect wring
How to Correct It