The library I worked for as a teen used to process off-site reservations by writing them to a text file, which was automatically e-faxed to all locations every odd day.

If you worked at not-the-main-location, you couldn’t do an off-site reservation, so on even days, you would print your list and fax it to the main site, who would re-enter it into the system.

This was 2005. And yes, it broke every month with an odd number of days.