CableFallbackCheck.ps1

$url = "https://datapass.de/"
$dataPassText = "Für den Aufruf dieser Seite ist eine Internetverbindung über das Mobilfunknetz notwendig"
$sevenIoKey = "" # API Key from SevenIO
$sevenIoPhone = "49176123456" # Telephone number
$sevenIoName = "FritzBox Fallback"
$sevenIoText = "The cable modem switched to the LTE fallback mode, this message repeats until script turned off"

Write-Host "Checking if $($url) contains a hint for beeing on LTE mode"
try {
    $response = Invoke-WebRequest -Uri $url
    $content = $response.Content

    if ($content -match $dataPassText) {
        Write-Host "The current mode seems to be LTE" -ForegroundColor Green
        Invoke-RestMethod 
            -Uri "https://gateway.seven.io/api/sms" `
            -Method Post `
            -Headers @{ "X-Api-Key" = $sevenIoKey; "Accept" = "application/json" } `
            -Body @{ 
              to = $sevenIoPhone; 
              from = $sevenIoName; 
              text = $sevenIoText
            }
    } else {
        Write-Host "The current mode seems to be CABLE" -ForegroundColor Yellow
    }
} catch {
    Write-Host "Failed to access the webpage." -ForegroundColor Red
}