speficication document for gravity connectors?

Hello DFRobot-Team,

is there a document describing the pin-out / voltage levels of the Gravity Connectors in generall somewhere?

in specific iam missing these details from the 

https://wiki.dfrobot.com/Voice_Module_SKU__DFR0534

wiki page - and therefore asked

https://www.dfrobot.com/forum/topic/334589

the connector itself seems to be identically with the Grove System one -

but the pinout seems to have VCC and GND switched.

https://wiki.seeedstudio.com/Grove_System/#interface-of-grove-modules

i don't understand how someone can do something that wicked.. 
 

that just caught me - i tried to use the SeedStudio Arduino Grove BaseShield to connect the Gravity Voice Module…
(inserting a 1k resistor as i found in the recommendations for the VoiceModule RX pin..)
and only after finding that something really did not workout (power led went off on arduino when connected )
checked every pin…

had never come to my mind that the same connector is used with inverse polarity…

sunny greetings

stefan