They did have write protection in the past... if I remember correctly, some of these memory cards really had an old-school Eprom you had to erase by UV light an

They did have write protection in the past... if I remember correctly, some of these memory cards really had an old-school Eprom you had to erase by UV light and externally erase using a high-voltage parallel programmer: http://www.classicautomation.com/Siemens_EPROMs.aspx http://www.classicautomation.com/Siemens_EPROMs.aspx