#set the COM port number here
$portno = 4
$command_string="Test`n"
$result1 = "NoRun"
$result2 = "NoRun"
$invalid = "Invalid system password"
$count = 1

Write-Host $command_string

$port= new-Object System.IO.Ports.SerialPort COM$portno,9600,None,8,one

do {
$port.open()
$port.WriteLine("$command_string")
$result1 = $port.ReadLine()
$result2 = $port.ReadLine()
$port.Close()

Write-Host $count
Write-Host $result1
Write-Host $result2

$count++
Start-Sleep -Milliseconds 10
}
while ($result2 -eq $invalid)