the 411 on dive computers...

ok....so talk to me about dive computers - i know nothing short of what i've assumed...and that ALWAYS gets me into trouble...
some seem to have an inlet for a line off your reg -
and i assume as such can offer total feeback remaining air/ pressure -as well as monitor the rate of consumption relative to depth and time etc.
others they say are' basic' computers these seem to fill the 300$ niche.(air only
and air + nitrox is obvious enough) they either fit in a console or your wrist,
others shoot up to 1500$ (some much more than that)and seem to be the high end of dive computers.And some of those seem to have a transponder which sits at the reg -wireless/hoseless communication from the tank i guess...
what are these high end units telling you that the 300$ units are'nt ?
what are the most basic of devices telling you?
do the high end ones have tetris on them to keep you busy during decompression ?
do some divers get rid of their consoles when they have a high end computer?
or is the analogue console retained regardless ?
give me the scoop... cheers - Marc

An awful lot of questions...

Split number one: nitrox-capable or not? Go for nitrox; not much more moola. If you want to dive with multiple gas mixes you pay more for more complicated computers.

If you want the computer to read your pressure (air integrated), you either need a hose from your high pressure port (in which case you have a console mount, where your pressure and depth gauges would have been), or you have a wireless transmitter in which case the computer is usually wrist-mounted. Personally, I'm contemplating the purchase of a wireless, air-integrated computer in which case I'll keep my tank pressure gauge as a backup, because the wireless transmitters are pretty good but not 100% reliable.

Do you want to download dive profiles to a computer? If so, do you use a Mac or a PC? For Macs the choices are more restricted; there are two good programs for Suunto computers.

Go for a simple display with big numbers in case you might ever dive in low vis or with old eyes.

Dive computers are fantastic for liveaboards, where the simplest use of tables (assuming that your entire dive was at maximum depth) with significantly restrict your bottom time. Some even carry two computers in case one fails!

Finally, Suunto have a reputation for having more conservative algorithms, which some prefer and some grumble about.

Said this in the other thread but it fits here too:

Audible ascent alarms are a useful thing. So is backlighting. Other people like a computer that can do 'gauge mode', which can be useful.

Downloading dive info to a personal computer as mentioned in the post above means you gotta have a PC (mostly) and even more specifically means you gotta have Windows XP (Not XP 64, Not Vista, and not Vista 64). But if you have a modern Mac, you probably can get by since you are probably using XP for boot camp. Using Parallels or VMWare Fusion may cause you more headaches than you want since the OS's like to fight about peripherals.

The basic computers are all most need. Tells you depth, time under, time left to decompression, ascent rate, and time your safety stop. They will also give you some other less important but sometimes wanted info like water temp. A lot will have a back light and audible alerts for ascent rate, oxygen toxicity, approaching decompression, depth limits. Pay a little more for the ability to switch between gas mixtures. The wireless ones use a transmitter to keep track of tank pressure. I think most people keep regular gauges for that. Heck even with a basic, may be a good idea to keep a depth gauge too. As for the console ones, I don't know if it estimates how much air time you will have left. The real high end ones have all the above, and yes some do have games to play for deco stops. They almost all can basically double as your log. The ones that can connect to a PC can let you see your dive profiles. Some will let you plan dives and simulate dives. It's probably best to have a full set of gauges for a back up and understand your tables in case of an emergency. Some people buy comps because they are large and easily read. Others get the small ones that double as there everyday watch. The Suuntu are very popular. A lot of people like the Seiko based computers which are the Cressi Archimedes, Tusa IQ700, Dive Rite Nitek Duo, and Zeagle N2ition. I personally have the Cressi and I got one for my wife too. Easily read, does a lot, very simple to use, can be connected to a computer, Nitrox, alarms if needed, simulate dives, and very inexpensive for what you get. I got my wifes for under $300.