I tried tc1232, but it is too sensitive for noise (100ns spike resets it). I tried 100nf accross 1232, but with no effect.
1) the noise senitivity of the 1232 varies from manufacturer to manufacturer, my (non-scientific) experience is that the MAX1232 is the most noise resistant.
2)on a board laid out by a (no I will not use that word in a nice forum) there were about 1 inch of trace from the 1232 to the 100nF decoupling capacitor. This board gave me the opportunity to try the different manufacturers of the 1232 and with the MAX1232 the false resets were the fewest, but it still took to solder a 100nF directly across the chip to make the spurious resets disappear. With that done we tried the various chips again and all worked, but we did, just to be sure, say MAX only.

Erik