The most common transmission medium for 50Km distances would typically be single-mode fiber. The typical range of this fiber would be about 40 miles without repeating, but there are new Eridium-based Single-mode Fibers that reportedly eliminate or reduce the requirements. I would suggest that you refer to ANSI/TIA/EIA-758 Standards for Outside Plant, and also the BICSI Customer-Owned Outside Plant Design Manual. Also contact Corning Fiber for more information on the Eridium-based Fibers.
50 Km of fiber would cost a lot. I would look into the possibility of adding one or two relay stations and
use laser or microwave. <nbucska@pcperipherals.com>
The answer to this question requires knowing what data rate your sending, is it continuous, is it secure data etc.
You can connect 2 offices to backup or sync small amounts of data by the easiest method of a land line at 56K. If you wish to send more data then go DSL or ISDN.
The cheapest method is if you have internet service at both offices you could connect that way (again for small amounts of data), mind you data security becomes an issue then.
If you don't have a landline provider then you can always look into UHF packet transmission systems (again depends on data rate and budget).
If you have an unlimited budget and can lay down 50K+ of fiber (mega bucks) then go that route.
