MicrolLogix1500 ASCII

Hi
I wrote a program in some time ago in Logix 500 v4.x (I think) using a MicroLogix 1500 (Series B). The customer has blown this PLC so I downloaded the same program to a new series C processor, but now I'm up to V5.0 Logix500. Everything but the ASCII comms works.
I couldn't test here, and now the PLC is with the customer (Iowa)
Anyone know of any issues with ASCII going up a version. I'm pretty sure it's Logix and not the new processor that's causing the problem.

thanks

pp

Can't answer your question directly, but here is a link to an AB knowledge base document about ASCII problems with version 5.2
Link