Benchmark Electronic Systems [P] Ltd. Manufactures Erbium Doped Fibre Amplifier [EDFA] Training System [ETS]. Benchmark Electronic Systems [P] Ltd. Offers Fibre optics laboratory systems, Fibre optic LANs, LAN trainer, Fibre optic video link, Fibre optic and digital communication experimenter, Fibre optic power source/meter, Fibre optic link, and Fibre splicing kits. The Erbium Doped Fibre Amplifier [EDFA] is an optical amplifier that amplifies optical signals sufficiently enough to cover several tens of kilometres without any need for conventional repeaters. All the blocks are given with proper input and output connections such that they can be configured in different modes of operation, such as co-directional and counter-directional operations. This modular approach also facilitates study of individual block characteristics wherever possible.