Delphi and COM port, what's the ideal code to read?

Question

Delphi

I use the BComPort library. I work with a barcode - pdf417. From some scanners it reads a barcode, from some it doesn’t, then it reads, then it doesn’t. What is the problem with this behavior of scanners? Where is the universal code for reading data? Scanners: Honeywell Xenon 1900, Datalogic Griphon 4400, Metrologic MS1600, etc.

Answer 1

Why do you need such masochism when there is a synaser?

Answer 2

Write your ideal code for working with a COM port using pure WinAPI.
Or give code examples, COM sniffer logs and all sorts of specifics in the problem description