This powershell script runs hourly via task scheduler and checks the number of MuliTech modems currently running against the amount that was running the last hour. If a diff exists send email to recipients. I wrote this script to monitor our outgoing fax server since RabbitMQ would not reflect a backup of faxes after handing off the message

MultiTechMonitor.ps1

function Send-ComPort-Alert 
{
   param([bool]$Asc, [string]$Modems)

   # Sender and Receiver
   $From = "sender@example.com"
   $To = "you@example.com", "me@example.com"
   
   # Server and Port
   $Server = "smtp.server.com"
   $Port = "587"
   
   # Credentials
   $Pwd = "Ex@mple1" | Convertto-SecureString -AsPlainText -Force
   $Creds = New-Object System.Management.Automation.Pscredential -Argumentlist $From, $Pwd
   
   # Content
   $Dir = ({'down'},{'up'})[!$Asc]
   $Subject = "WARNING: MultiTech modem went $Dir"
   $Body = "A MultiTech modem went $Dir.  Currently running $Modems"
   
   # Send Email
   Send-MailMessage -From $From -to $To -Subject $Subject -Body $Body -SmtpServer $Server -port $Port -UseSsl -Credential $Creds
}

# Get the last or initial number of MultiTech modems
$ComPortsCtPrev = (Get-ChildItem Env:COMPORTSCT).Value 

# Get current multitech modems
$ComPorts = Get-WmiObject Win32_PnPSignedDriver  | Where-Object {$_.Manufacturer -eq "MultiTech Systems"} | Select-Object FriendlyName 

# Check for difference between current and previous
$ComPortStr = $ComPorts | Out-String 
$ComPortsCt = $ComPorts.Count 
$IsDiff = $ComPortsCtPrev -ne $ComPortsCt

# If diff exists send email
if($IsDiff) 
{
    Send-ComPort-Alert -Asc ($ComPortsCtPrev -lt $ComPortsCt) -Modems $ComPortStr
}

# Update environment variable to be used as the next previous value
setx COMPORTSCT $ComPortsCt