Yes, tacticalogic doesn't know what he's talking about. In my shops, we were using IRMA boards in both Macs and PCs in the 1980s thru early 1990s, and there was no problem trading files around the network. They both "spoke" to our IBM mainframes besides to each other. I still have a Mac IIcx with an IRMA board, retired from its work in the mid 1990s. Before the Macs came along, I was using my Apple II at work linked to IBM PCs with off the shelf software in the early 1980s. No problem trading files.
You didn't get that IRMA board from Apple, did you?
When in the 1980's were you doing this? The MAC Driver Museum doesn't have anything earlier than 1991, and that's the earliest reference I can find for MAC IRMA adapters.