Fax transmissions include a confirmation process.
One of the reasons fax continues in use is that fax has a process to confirm that the entire message was received. When the receiving fax machine sends a confirmation signal, the sending fax machine prints a confirmation page.
As a backup, most fax machines keep logs of the time, date, number of pages, and success status of any fax transmissions.
You can tell if a fax is completely transmitted (and received by the other fax machine) if your fax has printed a confirmation page. It is a page that summarizes the time and date, number of pages, and destination fax number. It only prints when the sending fax machine has received a “message completely received” notice from the receiving fax machine.
A confirmation page is a proof of receipt of the message, in some ways like sending a letter using registered mail. Many people turn confirmation pages off to save paper. However, this means they no longer have their message receipt.
A successful transmission should show in your fax logs. These are records that show the time, destination, and success of previous fax transmissions. While they are not as detailed as a confirmation page, they can help show a historical record of communication.
You can tell if you got all the pages in the fax by checking the cover page and the fax logs.
The cover page should include the total number of pages in the fax transmission. This information should be written in by the person sending the fax. If you have the same number of pages as listed on the cover page, then you have all the pages of your fax.
The logs on your fax machine should also have the information of the time, the number of pages, and duration of recent fax transmissions.
Brother – Confirmation that a FAX I sent was received correctly – Instructions from Brother on how to turn on transmission verification reporting, which prints confirmation pages.
JustAnswer Legal – Is a fax confirmation receipt enough to prove that a fax was received? – A Q&A about whether a fax receipt is enough to show that a fax was received. Even if the message goes through, there may be other legal hurdles in getting a message through.
The Guardian (UK) – Is a contract entered into by fax as legally binding as a written or verbal one? – A discussion on fax as a legally binding document, and whether telex is better in some circumstances.
PC World – Why the fax still lives (and how to kill it) – An article on why fax machines stay around, and how to (maybe) get rid of them.