extract data from text file

[Mish]

I think you need to loop when you get to a START and exit it when you get to a STOP. Also this code caters for the specific text you specified at the begining of the thread. You can change it to the name of a variable and pass values of your choice into.

Dim iInput As Integer
Dim iOutput As Integer
Dim sLine As String

iInput = FreeFile
Open "c:\sample.txt" For Input As #iInput
iOutput = FreeFile
Open "c:\sampleout.txt" For Output As #iOutput

Do Until EOF(iInput)
    Line Input #iInput, sLine
    If InStr(sLine, "START 129, S") Then
        Do While Not EOF(iInput)
            Line Input #iInput, sLine
            If InStr(sLine, "STOP") Then
               Exit Do
            Else
                Print #iOutput, sLine
            End If
        Loop
    End If
Loop
    
Close #iInput
Close #iOutput