In 6.4, if using a Radiant 1520, 1220, etc pos terminal, part of PCI compliance is the change type type of your credit card reader in terminal settings. It must be set to OPOS with the name of the Radiant OPOS reader. If you do not, Aloha Manager will generate a verify report telling you the MSR's for those terminals are not configured correctly. In the 15XX Device Manager on the Terminal, several settings on the MSR table will be disabled and grayed out.
This is by intent.