EoW September 2011

technical article

test and troubleshoot, and the hourly rate of the installer required to install the network. That hourly rate depends on the skill set and equipment required to install the components. Major MDU architectures used for MDU deployments are shown in Figure 8 : a) traditional point to point solution – all fibres are individually terminated at the customer side b) blowing fibres – individual fibres/ cables blown from basement to the customer c) mid-span access – cable sheath is cut and fibres are selected and extracted on each floor d) pre-connectorised riser – 100% factory tested ‘plug and play’ solution The approach of a point-to-point as well as of blowing fibre has been to run individual fibre cables from a single point in the

All samples were put inside a walk-in chamber with two access jumpers on both ends. Samples were conditioned for 1h at each temperature and tested for 15 minutes. System measurements were taken before and after test exposure. 4 Deployment cost Estimations of typical first-installation costs of fibre to the home networks is shown in Figure 7 . Labour typically represents half of the first installed costs of fibre to the home networks while passive components represent only 20% of the total investment. There are two elements concerning the labour costs, namely the time to deploy,

Mandrel 15x cable diameter

Cable held firmly in place

Over- mold

Basket grip

To optical test equipment

Load

Cable

▲ ▲ Figure 6 : Sheath retention setup

The total pulling force during installation should not exceed 500N. Based on duct size, fill ratio and misalignment data, the maximum number of tap points pulled simultaneously can be calculated as:

▼ ▼ Figure 7 : Typical First Installed Cost [3]

(1)

Electronics 35%

Max. # of tap points

Where, F# is number of floors, MF is misalignment force and PF is pulling force.

Passive components 15%

Labour 50%

3 Reliability The qualification test plan was a variation of the GR-3122 specification, modified to reflect indoor usage. Test samples were prepared in the most common configurations; 6 x 4 – 6 tap points, each with 4f, 12 x 4 – 12 tap points, each with 4f and 12 x 8 – 12 tap points, each with 8f. For such a set of samples the following tests were performed: thermal aging, thermal and humidity cycling, sheath retention, cable flexing, compression, assembly installation, pulling through ducts, cable pulling and straight and 90° tether pull. All tested samples passed both environmental and mechanical tests without any issues. As an example for the extensive test programme the sheath retention test set-up is presented in Figure 6 . Test condition : The entire test was performed using typical indoor tem- perature cycles and an applied force of 500N (50kg). Two access jumpers were connected to the sample during the test. Optical monitoring of insertion loss was carried out both before and after the test.

▼ ▼ Figure 8 : Major FTTH architectures used In MDUs

a) Point to point solution b) Blowing solution c) Midspan solution d) Proposed preconnectorised riser cable

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EuroWire – September 2011