Yes, you can have more than 1 passkey for a BrainMaster module. For example, you could have a clinical passkey to use in the office and to set up the equipment, and also a remote unlimited passkey to use when the equipment goes home. Or, you could have 1 or more "calendar" passkeys, and use them to limit the time usage by the client. Or, you could have several "minutes" passkeys, each of which adds time to the usage of the equipment.
You might also have separate passkeys for other software, such as EEGer (NeuroCybernetics), BrainMirror (NeuroShifts), or BioExplorer (CyberEvolution), if you have purchased that software for use on BrainMaster hardware.