TI 305 & dos based software

Was able to download the ladder but there was a fault in the CPU saying the battery was dead but the light on the frount pannel didn't come on even with battery removed.
I purchased another CPU and tied to download program and can't get on line. using the SIMATIC TI30503dm interface. have it on an old dos laptop. using the original cable that worked just a few day ago. is there something funny about setting up the cpu to down load? Already removed battery to clear memory. Also now can't talk to original cup after the battery was removed. using com1 to adress 01

Jonwayne1951

One way, or another, you are not establishing a correct communication path.

How about checking your Baud-Rate?

using exact same computer with same cable and same settings just different results. downloaded the wiring for the cable and it checks out ok also

It could be that the rack/power supply is bad. That was always the component with the highest failure rate. There may not be enough power for the data communications unit.

Is the "PWR" LED on the face of the data communications unit lit? Does the "DATA" LED blink when the software is trying to establish a connection? Is the toggle switch on the right side of the data communications unit in the "Online" position?