Data Exchange Radio Networks for Railway Transport The article touches upon the problem of using conventional USF radio domains to construct mobile data exchange radio networks for automated control systems in raiway transport. These radio networks are considered as integral part of the RZhD unified technological system, which already uses GSM-R and TETRA communication standards. The performance characteristics of these radio networks make it possible to (i) considerably extend the capabilities of railway traffic data transmission, (ii) provide reliable functioning of the train separation system using a radio channel and satellite navigation means, and (iii) deploy additional data acquisition channels and channels to control railroad automation facilities.
I. Vlasov and M. Ptichnikov The article gives a short overview of the FTTx fiber-optic network concepts. Control, installation, and repair of FTTx networks are considered.
Nonlinear Distortions nd Nonlinear Noise in Coherent Communication Systems The influence of nonlinear optical effects on the performance of coherent DWDM communication systems with a bit rate of 100 Gbit/s over a channel is considered. Specifically, the influence of nonlinear effects on a coherent communication line is analyzed for two main application conditions: a 100-Gbit/s channel surrounded by 10-Gbit channels in lines with distortion compensation and a 100-Gbit/s channel in lines without distortion compensation. It is shown that nonlinear effects in compensated-dispersion fiber-optic communication lines cause amplitude and phase distortions largely as distortions of the transmitted signal shape. In long uncompensated lines, the influence of nonlinear effects differs consiferably and can be described as nonlinear noise generation.
Welding of Bend-Insensitice Optical Fibers Measuring data for signal losses at welds between frequently used AllWave ZWP optical fibers, including bend-insensitive AllWave Flex ZWP and AllWave Flex 200 mkm, from OFS Co.
are reported. Measurements taken with an optical reflectometer and optical tester demonstrate
that the root-mean-square signal decay at welds between bend-insensitive G.657 fibers and between G.657 and G.652 ones is no more than 0.02 dB.
Application of Time-Domain Reflectometers In scheduled maintenance and emergency work on cable communication and transmission lines, pulsed measurements are applied to locate irregularities and fails. Such measurements taken using time-domain reflectometers. The most frequently encountered errors made in inspecting cable networks with reflectometers are listed, and recommendations for the application and improvement of reflecrtometers are given based on theoretical results and experimental data.
New VoIP-GSM Gateways from Yeastar Co. The ways of extending personal and corporate communicaion capabilities using VoIP-GSM gateways are described. The diversity of the presented gateway line makes it possible to select an appropriae solution for busines of any scale.