RAILWAY METRO SDH

Railway Metro SDH Systems

AVD Technology is the sole procurement source for the supply, installation and maintenance of SDH and primary multiplexer products used in railway, metro and electricity transmission systems.

SDH equipment are the basic carriers for the railways signaling system. Guaranteed communication speed, predictable delays, no interference between different applications and redundant paths in less than 50 ms in a ring architecture are the main reasons for choosing SDH.

In the simplest sense, SDH is a fiber optic transmission system with 2/34/45/155/622 Mbps carriers. These carriers are used to carry information such as E1 and Ethernet.

Since different carriers are used for different information in the SDH system, different information does not affect each other. The speeds in the SDH system are called STM1/STM4/STM16/STM64.

SDH is the backhaul for telecom operators and critical networks. SDH, which is currently the basic transmission medium for technologies such as GSM, GSM-R, Tetra, is used very intensively.

In railway infrastructures, next generation signaling systems operate over Ethernet. Therefore, Ethernet over SDH (EoS) is the most widely used technology in railway systems.

SDH systems can switch at a speed of nx2 Mbps. Only voice signals, serial port devices and ports such as FXS/FXO/E&M are transmitted at 64 Kbps. This type of information cannot be carried directly over SDH. Therefore, multiplexers capable of switching at nx64 Kbps are needed to carry this information. These products require the use of a primary multiplexer. These products are usually called PDH.

PDH products usually have 2 Mbps E1 uplink ports and can multiplex at nx64 Kbps.

As AVD Technology, we have a wide portfolio for SDH and Multiplexers.