TM-D710 / Packet Connection
Realize that the USB-K5G is made to replicate the original serial cable from Kenwood, PG-5G. Whatever that original cable can be used for, the USB-K5G will work in its place.

As for packet, the manual for the radio states on page 11

This terminal is for connecting to a PC (this is the 8-pin connection on the back of the head) using the PG-5G (option) cable. Based on this statement, the USB-K5G will work.

Note: Remember, this is not the port through which the radio programs.