What would be the best media to use to connect 2 devices 2500' apart? What devices would I need to convert to CAT5 at the ends?

The best media to use would be fiber, in fact, if you want any real bandwidth, I believe fiber will be about your only choice.

You could use multimode without any trouble, and the electronics are much cheaper.  So you need two strands of multimode fiber between the two spots, then a media converter on each end that converts the fiber optic signal to 10 or 100 mbs ethernet.  

That's all there is to it, you can find quite inexpensive used stuff on ebay, or if you want to look at the high end of prices Black Box has a pretty good web site that can help you select what you need.  Do keep in mind that multimode fiber for this will be terminated in either an ST or SC connector (generally) and you need to get converters with fittings to match.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

First let me agree that fiber is the right answer, this may be the best wrong answer, however:

http://www.tutsys.com/products/mtu/ethernetworking/xl_4000/index.cfm

I tried to remain child-like, all I acheived was childish.

I agree with fiber  you can buy the fiber cut to lenght and pre-terminated if you dont have the tools  or you can pull the fiber and hire someone to terminate.

  the item that jimbopalmer linked to looks interesting but it does limit you to 10mbs plus you  now have to look at lightning issues.

  

From my experience 1500' is what you can expect to get from Multimode fiber. To go 2500' you will have to use Singlemode fiber.

I respectfully disagree. I have several multimode installations in excess of 1500' working with no problem on multimode fiber.  Of course it does depend on the the speed you want to run on there and the quality of the fiber, installation and equipment.

According to the BICSI Telecommunications Distribution and Design Manual, which I realize is not the bible but certainly a valid source of information:

As a general guideline in premises applications for backbone cabling:
*62.5/125 um or 50/125 um multimode optical fiber is recommended for distances under 2km (1.2 miles) and data rates up to 155 Mbs.
*single mode fiber is recommended for for greater distances or higher data rates

Now if you are going to push it to gigabit ethernet, it is a bit more critical, however General for one makes a Gigabit fiber for up to 600 meters and there are others with similar products.

Short simple fiber hops are obviously easy to do, you can get almost any fiber and any tranceivers and make it fly.  As you approach the upper limits of distance and/or bandwidth, one should give some serious thought to having the circuit designed and tested when installed to insure that you get what you were intending.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

Go fiber with allied telesyn RJ45 converter at both ends,

Works great for me!!  i used for 2 different sites. Never add problem since it was installed.

Must be different for networking then for cameras. I install seurity equipment and all the fiber devies I have used (mostly video) say 1500' on multimode. Only recently have I been getting into networking.

Jeff the (nortel) specs I have say 2km at 10 and 100mbps for multimode

gig fiber  is pickier, 250/550 meters for 62.5nm SX/LX, and 550 meters for 50nm, so gig prefers single mode (5 km to 70km although greater than 5km is not to a standard)

I tried to remain child-like, all I acheived was childish.