Not really sure how accurate that is....most ticket printers, magnetic card readers, weigh scales, barcode scanners, and other POS related devices adhere to the Unified POS standard.

There is a Java implementation of the standard (called, unsurprisingly, JavaPOS) as well as a .NET implementation (called POS for .NET). I've run a Linux based point of sale that used JavaPOS to interface with peripherals without issue.