According to the rules set down by my college, I am in fact allowed to use third party code in my project provided that I give credit to the original author of the code. Since the DTMF part of my project is only a minor part of the entire thing (less then 10% I'd say), I would easily be able to get away with using someone else's code as long as I was upfront about it.

With that said... I have a low budget and spending money on software for me is a waste of money. There's nothing in software that I (eventually) couldn't figure out how to do myself. And eventhough I can get it for free as well, my reasoning for using hardware is still:

1) Size. I'm using Keil evaluation which is restricted to 2K of memory. I may have to move over to the lab computers towards the end of the project, which have full versions installed, but I'd like to keep building the software on my laptop for as long as possible. For that ASM is the way to go (or so I've been told).

2) It's easier. Between reading datasheets, making a schematic, writing the ASM controller code and making a breadboarded prototype, it would still take me longer just to make the C code and get it working (even if I used the example code from this website).

Anyway, I hope people don't start fighting over this since it's really no big deal. I've found the parts I need at Mouser and I will most likely order them from there. Thanks again to everyone and their suggestions.

To Kevin:

Yes I was actually looking for Zarlink parts but I couldn't find anyone who had them for sale. Like I said, I found some similar parts at Mouser so I've kinda decided to go with that. But I'll probably check out Avnet anyway to see what kind of price I'd end up with if I ordered everything from them. I appreciate your input.