The Secure Write Mechanism can process one parameter write at a time for a given SIS module. Also, only one command (Lock, Commission, and so on) to a given Logic Solver can be handled at a time. Each desktop has its own independent secure write behavior. This means that the secure write confirmation dialog will appear on the desktop from which the application was started. The behavior of secure writes depends on the type of SIS system.
When a change that requires a secure write is made the secure write request is sent to the controller where it is stored and a response returned. When the secure write server receives the response it either displays an error message if there was an issue or it displays the confirm dialog. When the secure write is confirmed the secure write server sends the confirmation to the controller which then validates this against the stored request. If everything agrees then a single message is sent to the SLS1508 which then processes the request and returns either a success or failure to the controller which in turn sends it to the secure write server.
From the perspective of the secure write server the CSLS works the same as in the SLS1508. However when the SIS controller receives the secure write request it simply sends it to the CSLS which validates and stores it and sends the response. When the secure write confirm is received by the SIS controller it again simply sends it to the CSLS where it is processed and a response returned.