The main functions of the OSF (and mounted subracks) are to provide: a managed standard fibre installation, reticulation, interconnection, distribution, re-arrangement and maintenance activities at a common point. It also allows for fibre testing and fault finding activities.
The double sided Optical Suite Frame (OSF) is generally located at the end of a back to back suite of optical equipment racks, and feeds the optical equipment using long length patch cords. The patch cords run in the overhead ducting system. The OSF features a termination side and a patch cord side; where each side of the OSF is (again) divided into a higher and lower half. This allows two large fibre groups to be managed separately. The patch cords are managed in an orderly and effective way in the patch cord side of the OSF. They travel from 2 x 5 x 2RU subracks, that are housed in the higher and lower (half height) termination side of the OSF. The OSF has a fibre count of 2 (groups) x 5 (subracks) x 72 (fibres) = 720 fibres, up to 2 x 5 x 96 = 960 fibres. The MBR of every optical fibre cord is maintained at 30mm throughout. One subrack is provided initially, with the remainder added with growth over time.
A major feature of the subrack is the minimum amount of movement that occurs to loose tubes and optical fibre cords, as the subrack opens and closes. This ensures a very high degree of protection for working services. Also, the fusion splices and pigtails are located in a protected position, because there is very little chance of them being disturbed when patch cords are being installed, as the subracks tray only needs to be opened a very small amount