NetListener

You can use this software if you have some criticle devices in your network, and you have to check if this device is living or not. Or may be you want to look if there is somebody logged in whith the Modem, you can also use "Netlistener".
With Netlistener you can run Applications on disconnection or on connection from Computers on your network. It also loggs the status of your Computers or devices which you are watching.