|Courtesy of http://www.networkmuseum.net/|
Running fiber between exchanges was a different matter - the number of premises is low (less than six thousand nationwide,) the routes between them already identified with existing cable runs, and the reqirement for fiber counts is high - it made sense to run bundles of hundreds of strands of fiber on these routes.
So there came to pass two ways of running fiber. One suited to low-density installations - where few high-value customers in random locations need a dedicated link and the other suited to fiber-rich high-bandwidth readily identified premises.
|Armoured Fibre Cable for Direct Burial|
Deploying blown fiber also has a cost - it could turn out to be dearer than direct burial or OHP. The fiber inside costs basically the same so the cost difference is the expensive ducting system (and apparatus to operate it.) Blown-fiber technology suits the deployment model for the national telco with random site connections coming in according to customer orders, with third-party contractors doing the digging. A rural broadband project is engineered differenctly - the target area is to be flood-filled with access network in the same dig, with all the planning and engineering problems solved in one go.
The second drawback with blown fiber is maintenance - traditionally installed broken fibers are easily fixed by digging and splicing new. Duct systems are more time consuming and costly to repair (even the unused ducts have to be made good) and the manufacturers recommend that broken fibers are blown out and completely replaced in the event of a break, increasing the cost and time-to-fix.
So if you are contemplating a rural fiber install, please consider the simpler approach of installing regular fiber cable day one rather than a blown fiber system, you might save money and it will be a lot easier to repair when the rogue JCB strikes.