Yes, I have seen this port in my Alto too. The last time i complained about my power steering losing power and working as Manual at time and a "thud" sound while driving on potholes, Maruti service center has connected some device through this port which looks like a fat tennis racket to check the complete system/car details. They have charged 300/- for using that device. Finally it indicated towards the fuse box as faulty and the fuse was changed to solve the issue for good.
I guess all models have it from Omini to Latest in Maruti to my old bolero(2007).(not sure of other cars).
Obd need 6code to connect or complete connection usually except maruti rest car company after 2004 has same type of code so software easily know how to connect. Like my obd work with 2005 carolla but not with my 2003 as it use different code which obd software doesn't know