COM Port not working

[oyg3n]

I tried the latest stable/unstable versions.

hier is the trace from the start of the program:

2e80:Call USER.200: OPENCOMM(12e7c466 "COM4",0400,081b) ret=1777:6cb0 ds=12e7
3168:2e80:trace:comm:OpenComm16 COM4, 1024, 2075
3168:2e80:trace:comm:GetCommState16 cid 3, ptr 6F43FEC8
2e80:Ret USER.200: OPENCOMM() retval=fffffffc ret=1777:6cb0 ds=12e7

tarce_4.txt

[cracyc]

Error -4 means that SetupComm, https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setupcomm, is failing. It doesn't show why.