I am not familiar with this radio or cable. However, if the programming cable plugs into the same connector as the speaker mic, check the radio's menu settings. On my Kenwood TH-F6A, there is a menu item for setting the speaker mic connector for a speaker mic, packet operation, or the programming cable. If this menu item is set to speaker mic, the programming cable will not work. Conversely, if it's set to programming cable, the speaker mic will not work.
73, de Tom, KA1MDAwww.ka1mda.org