I believe they actually want to connect the Arduino to a device that has a serial interface. The Arduino can do this, but you will most likely need to convert the ttl to rs232 voltages. There are several ways to do this. You could build your own circuit using a max232 chip or buy something like this from sparkfun.
You are correct.
I just bought the kit from sparkfun; I figure the less I have to build/design the less chance for error. Anyway, i'll attach that to the in/outputs of the arduino. Is there a simple way I can send/recieve hex in the arduino language. Forgive me for a being a newb, there's just so much information to sift through and I dont have very much time; easier to ask a direct question.