Parameter Description for PIDs declared by SubDevice - E1.20 RDM (Remote Device Management) Protocol Forums

prwatE120 · February 24th, 2016

There appears to be a hole in the E1.20 standard in that there is no logical way of getting the Paramater Description of a Manufacturer Specific PID that might appear in a SubDevice's list of supported PIDS.

It appears that we unnecessarily restrict the GET:PARAMETER DESCRIPTION PID to be sent only to Root Devices.

ericthegeek · February 24th, 2016

Including my thoughts here for the discussion (Peter and I discussed this earlier):

Manufacturer specific PIDs are supposed to be the same for all devices from the same manufacturer, Thus, as long as you can get the PARAMETER_DESCRIPTION for the Sub-device's PID from somewhere, it will give you the information you need.

Thus, you could send a GET PARAMETER_DESCRIPTION to the root to get the description for a PID that is only supported in the Sub-Device(s).

Just because the root gives you a description for a manufacturer specific PID doesn't automatically mean that the root supports that PID.

While reading through the E1.20 doc, the same question applies to STATUS_ID_DESCRIPTION. It can only be sent to the rood, so you'd have to ask the root for the description of a status code that was returned from a sub-device. This may be less of a concern though, since STATUS_MESSAGES should only be sent to the root device.

February 24th, 2016	#1
prwatE120 Task Group Member Join Date: Jun 2006 Posts: 181	Parameter Description for PIDs declared by SubDevice There appears to be a hole in the E1.20 standard in that there is no logical way of getting the Paramater Description of a Manufacturer Specific PID that might appear in a SubDevice's list of supported PIDS. It appears that we unnecessarily restrict the GET:PARAMETER DESCRIPTION PID to be sent only to Root Devices.

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February 24th, 2016	#2
ericthegeek Task Group Member Join Date: Aug 2008 Posts: 379	Including my thoughts here for the discussion (Peter and I discussed this earlier): Manufacturer specific PIDs are supposed to be the same for all devices from the same manufacturer, Thus, as long as you can get the PARAMETER_DESCRIPTION for the Sub-device's PID from somewhere, it will give you the information you need. Thus, you could send a GET PARAMETER_DESCRIPTION to the root to get the description for a PID that is only supported in the Sub-Device(s). Just because the root gives you a description for a manufacturer specific PID doesn't automatically mean that the root supports that PID. While reading through the E1.20 doc, the same question applies to STATUS_ID_DESCRIPTION. It can only be sent to the rood, so you'd have to ask the root for the description of a status code that was returned from a sub-device. This may be less of a concern though, since STATUS_MESSAGES should only be sent to the root device.