I’ve been collecting a summary of the proprietary extension commands for NMEA GPS modules based on the MediaTek (MTK) chipsets.
Here (click to download Excel file) is the summary of all the $PMTK commands I’ve found so far. The source documents (which you’ll need for details of the parameters) are on the Web – ask Google for them.
Not every command will work on every module. You can find out if yours supports a given command by sending it and watching for the response. $PMTK001,code,3 means it worked.
Many of the commands have three variants – a code that sets a parameter, another you can use to query the current setting, and a 3rd that the GPS uses to reply to the query.
If you know of others not in the list, please contact me (as much detail as possible please) and I’ll add it.