It sounds like several different protocols are supported. The DB9 jack is intended for use with an adapter you can wire yourself. Basically just tap into the terminal block on the alarm ...

The 2010 Aston Martin DB9 is the epitome of a luxury GT. Hand-built at Aston's Gaydon facility, the DB9 is a race-bred car that easily delivers triple-digit speeds, plush interior ergonomics, an ...