"OER" and "ZTC" are often used interchangeably but they are not necessarily the same thing. Here's how they're different.
Open Educational Resources (OER) carry an open license. -- Creative Commons - CC which grants permission to access OER materials for free along with the permission to modify the work in the following ways:
ZTC stands for Zero Textbook Cost and is a broad umbrella term for courses where there are no required textbook related costs. These courses may use a combination of openly licensed content, links to scholarly or professional websites, library resources, original content, or other free resources for students. In many cases, ZTC courses utilize a curated collection of many resources rather than a single text.
Some of the learning materials may cost the students zero dollars but a cost is incurred somewhere. For example, materials from Western Library's resources are considered ZTC but not OER. Why?
"Open Educational Resources (OER) are educational materials and resources that are publicly accessible meaning that they are openly available for anyone to use and under some licenses to re-mix, improve and redistribute."
From "Discovering Open Educational Resources (OER)" by Steven Bell.
Re-used thanks to a Creative Commons Attribution-Non-Commercial-ShareAlike 4.0 International License
One of the benefits of OER is the capacity to link students to a page, section or chapter that addresses the particular competency or skill you are trying to teach by inserting the link on the relevant Blackboard page. Often sections and pages are shorter and more to the point than a traditional text books. Linking in this way is a great way to customize or "remix" OER content that serves your needs.
1. OpenStax is a non-profit educational technology initiative begun in 2012 and based at Rice University. The service is web-based and free to adopt, use, and revise due to it's open copyright license. Peer-reviewed textbooks are authored by experts in their fields and updated and revised when it becomes necessary.
2. Open Texbook Library (University of Minnesota) is part of the Open Education Network based in the Center for Open Education at the University of Minnesota’s College of Education and Human Development.
3. Libre Texts curates open content that can be used either directly or as content for building customized remixes.
In addition to the general links below, this page contains examples of OER in each of the programs linked at the left.