(keitai-l) Physical connector spec

Hi,
I've been trying to find information on the connector on the bottom of 
docomo (and other) phones. I know they can be connected to a PC to update 
the address book, but I wondered what else can be done, and how I go about 
writing PC software to use the connection.

Is the spec on the interface available anywhere? Is it safe to assume it is 
standard across all manufacturers for the same carrier? Is it also stable, 
or do new functions get added with each new model number?

Thanks,
Darren