When only the CPU is plugged in green cpu light flashes at 15sec intervals

On the backplane, pins 1 & 2 are common. +5 vdc on 83 & 84 (2nd row from top). +12 vdc on 7 & 8 (4th row from bottom) -12 vdc on 79 & 80 (4th row from top). 11.8 to 12.2 is the acceptable range for the 12 v +/-. This is right out of the Troubleshooting section of the manual.

Hyperterminal is a terminal emulator program, it is free to download for Windows. It gives you a basic interface like just having remote fast. This is how you talked to TIII and TIV controllers before IMS. The settings are 1200 bits per second, 8 data bits, parity= none, flow control=hardware. Just plugging in with Hyperterminal and resetting the CPU will run the confidence test.
One other thing you might try is breaking off pin 4 of your 25 pin cable or adapter. This would only work if everything else was fine but you just couldn't talk to the controller.

Thanks for the help in dirt....checked the 12v+/- on backplane and definitely not getting voltage there...5vdc ok...compared voltage on another car in the group with same readings,yet no problems with that car... yesterday I changed 12v battery in bottom of controller...awhile later ims started seeing car#2 intermittent ly then loses comm...it says no comm when I can get to the screen..weird...so...if I turn car on,cop car calls all latch,cop fire Svc light comes on,hall up/down directionals on at every floor,and all up/down calls for group latch at all floors sending other 3cars chasing them...when all calls are answered, things return to normal except the hall directionals stay lit....Oh and car won't run in any mode...inspect,normal,etc....

I'm not sure about that 12v supply, I thought it had to have it, must be wrong. I think you need to get Hyperterminal and plug in that way. But if you have a new CPU powered up, with nothing else plugged in, you should get comm. unless there is a problem with the software or EPROM chips. I vaguely remember something similar from a bad EPROM chip.

Units back up and running..Turns out to be bad stabilent left oily residue on boards...cleaned and dried all boards and backplane, plugged all boards back in and car communicated immediately....

Thanks for all the responses ..it is appreciated