Kolejowe Zakłady Łączności (Telegraphen Werkstatt) was first mentioned in 1852.
It was when telegraphic workshops were founded as a part of the Royal Directorate of the East Railway with their office in Bydgoszcz. The workshops dealt with the problems of the railway operation in the east. Their task was the repair of aerial telecommunication lines, the telephone and telegraphic equipment.
In 1920 Warsztaty Sygnałowe was established; its operation on the route Berlin – Bydgoszcz was the beginning of the present Kolejowe Zakłady Łączności.
After the war it was the only company in Poland belonging to the ministry of railways, manufacturing special communications equipment for railway purposes. The company also installed automatic telegraphic exchanges and repeatable telegraphic devices, which it put into operation in the entire network of the Polish Railways (PKP).
The business boomed in 1960-1970. At that time the company was hailed by the Ministry of Transport as the base for the development of the Polish Railways in the area of communication devices and passenger services. In 1996 the company was transformed into a commercial law company.