When one PC has both an LocalTalk PC Card and a Centram TOPS card, problems
(unrecognized cards and malfunctioning printing) that may occur might be
isolated by testing each card separately for all functions and making sure
both COM ports are free (the LocalTalk PC Card needs a free COM port).
You should also check the DMA settings of a file for the TOPS card,
config.sys, and the switches for the cards for Centram TOPS and LocalTalk PC.
The DMA settings must be compatible, e.g. config.sys with DMA=1, Centram TOPS
card with switches set for DMA=1, and LocalTalk PC card with switches set for
DMA=3.