Fibreoptic Industry Association publishes splicing Technical Support Document that will form an independent basis for project specifications in the rail industry Released 30 July 2004 Optical fibre technology has long been central to rail industry communications infrastructures, whether as the transmission medium for signalling and alarm systems, or as the carrier for retail telecommunications such as Public Address, CCTV and Passenger Information. The fact that fibre is by definition inert is a leading factor in safety-critical rail applications, as is the cable's ability to run trackside for long distances with minimal attenuation. For bandwidth hungry applications such as CCTV and video, fibre-based transmission infrastructures really come into their own. Fusion splicing is a long-established and well-proven technique for the provision of low insertion loss and high return loss joints in fibre optic cable. Unfortunately, unrealistic demands for splice loss performance, flawed in terms of what is specified and/or how it is specified, are often included in project specifications, causing problems for both installers and clients. To overcome this problem, a working group, chaired by the FIA's Technical Director, was convened. Key players from the installer and instrumentation sectors of the fibre industry worked together to produce a commercially viable set of splice loss specifications, which if followed, will ensure that the operation requirements of the system are not compromised. The document, TSD-2000-4-1-1, is a free download from www.fibreoptic.org.uk to FIA members and available to non-members for a nominal £75 from the Secretariat, 01763 273039, jane@fiasec.demon.co.uk. The TSD adopts the commonsense approach of placing most emphasis on the optical budget of the channel, with the loss level in any individual splice only being of interest if it is greater than 0.3dB, a level that will almost certainly indicate faulty workmanship or subsequent cable damage. However, particular problems arise in singlemode fibres, where the most significant cause of splice losses is mode field diameter mismatches, a problem compounded by the existence of 5 different types of fibre cable specified in IEC 60793-2-50 (and 13 sub-types within ITU-T specifications). The TSD allows for the various options likely to be faced in the real world by setting out splice loss limits for joints between "same product", "same generic type", "different type" and "unknown" types of singlemode cable. For contractual and operational purposes, the TSD recommends splice loss averages for different cable types and also discusses technical and commercial issues associated with reworking. *** Ends: body copy 287 words *** Notes to Editors. For further information: FIA contact: Jane Morrison Fibreoptic Industry Association The Manor House Buntingford SG9 9AB tel: 01763 273039 fax: 01763 273255 jane@fiasec.demon.co.uk www.fibreoptic.org.uk Agency contact: Nigel May Parkfield Communications Limited Parkfield House Damerham SP6 3HQ tel: 01725 518321 fax: 01725 518378 nigel.may@parkfield.co.uk www.parkfield.co.uk The Fibreoptic Industry Association represents more than 80% of UK companies involved in the manufacture or installation of fibre optic components and systems for voice and data communications. The Association provides advice to end-users, runs training and qualification services for its members, contributes to the development of national and international standards and generally represents the interests of the fibre industry. Its web site, www.fibreoptic.org.uk provides a free online reference service to all visitors.