The company, located in Berlin-Kreuzberg, specialised in manufacturing electrical telegraphs according to Charles Wheatstone's patent of 1837. In 1848, the company constructed one of the first European telegraph lines from Berlin to Frankfurt am Main. Siemens & Halske quickly expanded with representatives in Great Britain (Carl Wilhelm Siemens) and Russia (Carl Heinrich von Siemens) as well as its own cable-manufacturing plants at Woolwich and Saint Petersburg.