Hewlett-Packard offers a faxing service that allows you to test fax completion.

If you send a fax to HP Test Fax 8884732963 you will be able to confirm outgoing fax completion.

They have an automated system that will then send you a test fax to confirm incoming fax completion. Sometimes this service is down for maintenance, please try using an alternate fax number if your faxes fail to this destination.