Are they different? i can't seem to find a straight answer using Google....
That's sort-of because you're not asking a straight question.
RS-232 is a signalling standard, and DB9 is a connector standard. Most cables that are intended to carry RS-232 signals, have DB9 connectors -- but some RS-232 cables have different connectors, and some cables for other signals have DB9 connectors.
The Empeg cable is suitable for RS-232 (and has DB9 connectors). The only gotcha is that there are two possible ways of wiring up such a cable: "null-modem" and "straight through" (though "straight through" are usually female-to-male). The Empeg one is "null-modem". If your Empeg cable fits the connectors for your firmware upgrade, it'll probably do the job.