Q: How do I send text notifications to my phone? Do I really need to buy and configure a modem for this?
A: No. You can set up email notifiers to the addresses on sites like this and your carrier will forward them to the phone number you include on the address.
Caveats:
If the network problem requiring notifier launch involves the path to the Internet, guess what?
The addresses may be outdated if the carrier changes them or drops the service. Verify, check periodically, and configure a backup notification.