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Old May 1st, 2012   #11
ericthegeek
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Join Date: Aug 2008
Posts: 369
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Scott, you and I are talking about something different.

On the root device, the standard says that the list of PIDs returned by GET SUPPORTED_PARAMETERS does not include the mandatory PIDs. For example, the list returned by the root device should not include SOFTWARE_VERSION_LABEL since SOFTWARE_VERSION_LABEL is required. This, a controller would normally not expect to see SOFTWARE_VERSION_LABEL in the list of supported parameters.

But, the same rule does not apply to sub-devices. When you send a GET SUPPORTED_PARAMETERS to a sub-device, the list of PIDs should include SOFTWARE_VERSION_LABEL. Thus, when getting the PID list from a sub-device, a controller can expect to see PIDs included in the list that would never be returned by a properly implemented root device.
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