had these for years usually program from back serial of xp machine using one connector in serial computer and the motoropla clamp that goes onto the contacts at side of radio, using the cps 4 and I purchsed 6 a while back, the cable seems connected properly the port is showing when asked to read the radio, which is switch on it says cannot open port make sure switched on. is there a button sequence I must use to put mts200 into programming mode or ?, I have two similar programming cables tried different xp machine with serials and they both said the same, cannot connect check the radion is switched on this is com 1, i tried via a usb serial cable to get another port same thing, is there buttons on the radio I must press to allow the radio to talk to the cable and computer. thank you in advance, David