Assess each layer
| 32-bit application | COM APIs generally remain available, but port-name and installer assumptions may fail. |
|---|---|
| Driver/interface | PCI/USB/PCMCIA hardware may lack supported drivers. |
| COM numbering | Hard-coded low ports or per-user configuration can block use. |
| Timing/control lines | Replacement hardware may alter latency or handshake behavior. |
| Security/deployment | UAC, protected paths and unsigned drivers affect installation. |
Choose native or isolated operation
Test a clean Windows 11 installation with representative operations and captures. Native use fits when drivers and behavior are supported. A VM can preserve software but may not reproduce direct PCI/ISA or timing-sensitive hardware. An isolated old PC may be temporary risk control while a gateway is developed.
Use virtual COM integration, USB adapter analysis, capture comparison and the pillar.
Provide hardware IDs, drivers, original/target Windows, application architecture and known-good traffic.