Building the railway communication exhibition – part 2

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Another stage after placing carrier telephony racks on their place was the assembly of main switchboard (so called cross). This stage took place between March and May 2016. Switchboards are vital parts of each automatic exchange which allow for grouping of each of the functionality. This, as we would call it nowadays, architecture allowed for rational division of equipment between specialized racks, their replacement, extension or even bypassing a fault.

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One can find two types of switchboards in telephonic exchanges – main and intermediate – different when it comes to function. Main switchboard is mostly a separate piece of equipment, large enough to have a separate room. It is a sort of an interface of the exchange. Here are connected, from one side the customer and inter-exchange lines (so-called line side), from the other side cables of specific equipment in the exchange. Switchboard allows for quick reconfiguration of connections e.g. change of customer’s telephone number. The intermediate switchboards are actually an integral parts of connecting equipment. They connect each stage of step-by-step number selection as well as additional equipment, allowing the exchange to work as a whole.

A common practice at Polish State railways, was to use only intermediate switchboards, providing that exchange was small (less than 300 numbers) and served small traffic. Such solution was present in the temporary exhibition we created back in 2009. In case of large exchanges e.g. for main railway district office, next to a massive main switchboard were placed two or more intermediate switchboards to keep the rest of the exchange smaller and cut on the length of expensive cables.

While assembling our main switchboard, we had to complete some metalworking. The original switchboard was recovered in parts – we had a number of original spans and a couple of to long horizontal bars. Also the baseplate was missing and had to be created anew. Afterwards, all parts had to be cleaned from rust and multiple layers of old paint, and repainted. After placing on new wooden base, the switchboard sufficient for the capacity of future exchange was mounted in target place in May 2016.

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