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I would not worry too much about a DC for now, rather use the tables as a start until you know what your needs are. Someone in the dive group will have a DC, stick with them or the DM. If you have the spare cash, you could consider a Suunto Gekko, Hollis DG 02 or Oceanic GEO 2.0. Search the internet do some research. You will quickly get a feel of what your requirements and budget constraints.
I'm a new diver that is looking to buy a computer with basic functions. ....... I would appreciate any advice. Thanks!!!