Hi Brian,
This post will refer to the most current EFIS-D10A installation manula -Rev. B - which is available at www.dynonavionics.com.
In particular, check out the second half of page 12 of the installation manual. The table there describes the pin outs on both the 9-pin serial connection on the EDC end and the corresponding pins on the EFIS-D10A's 25 pin connector. Essentially, you are connecting 4 pins from the 25 pin EFIS connector to 4 pins on the 9 pin EDC serial connector.
