Telecommunications test methods

A draft European Nebulizer Standard (30) has been submitted for formal approval to CEN (Comite Europeen de Normalisation European Committee for Standardization). CEN is responsible for European standardization in all fields except Electrotechnical (CENELEC) and Telecommunications (ETSl). Publication of the European Nebulizer Standard is expected during 2001. Included within the European standard are detailed descriptions of two test methods for (1) assessing nebulizer aerosol output inhaled using breath simulation similar to that described previously and (2) assessing nebulized aerosol droplet size using low-flow cascade impaction. Because this standard is expected to be adopted throughout Europe (and possibly more widely), a summary of its contents may be useful to readers. 

D4565 Test Method for Determining the Physical/Environ-mental Performance Properties of Insulation and Jackets for Telecommunications Wire and Cable D4591 Test Method for Determining Temperatures and Heats of Transitions of Fluoropolymers by DSC D3012 Test Method for Thermal Oxidative Stability of... 

Some of the telecommunication cable plant components are made with met2ils embedded in polymers, and the metals are exposed to the corrosive environment only at very small areas (e.g., edges or sm2dl defect sites on the polymer). Test methods are used to ev duate the penetrability of the metal-to-polymer interface and the ensuing progressive corrosion of the metal. 

The test methods used to evaluate the corrosion of materials and plant components are described in Bellcore Technical Advisories (TAs), Technical References (TRs), and Generic Requirements (GRs). Many of the tests in these documents include and reference ASTM, UL, ANSI/NEMA, and MIL standards. Some of the test methods are specific to the telecommunication industry and can be found only in TAs, TRs, and GR s. Manufacturing and purchase of telecommunication plant components are based on these documents, thus, available to the manufacturers and to companies that sell them. The methods used for in-plant testing are described in Bell System Practices (BSPs) and licensed Bellcore documents. ... 

In the 1970s, telecommunication companies in the United States and Europe predominantly used rosin fluxes for their wave-soldering requirements. These companies had their own internal set of test methods for seleding noncorrosive rosin flux formulations. Using their selection criteria, they beUeved the fluxes to be sufficiently safe. For their applications, they cleaned only the bottom side of the assembly, where rosin residues needed to be removed to ensure good electrical contact during bed-of-naik testing. 

ASTM D 4565 [450] Standard Test Methods for Physical and Environmental Performance Properties of Insulations and Jackets for Telecommunications Wire and Cable... 

The electrochemical migration test requires that any degradation in insulation resistance value be less than a decade. The Telcordia Electrochemical Migration test method has also become an IPC test method (TM 2.6.14.1). Table 1 compares the variation in SIR and electrochemical migration test conditions for telecommunications test versus the non-telecommunication applications. 

The metals and plant components are tested by methods described in national standards. Some of the plant components and the in-place plant are tested according to methods and requirements developed by the telecommunication industry. 

In order to determine the availability rate of emergency response network, transition rate between defined system states has to be known. Numerical values of those parameters could be estimated based on reliability prediction methods. This is justified for newly built systems. Operational tests or empirical data from system elements testing can be the other way to obtain those numerical values. This pertains among other to estimating parameters of fibre optic telecommunications networks. 

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