The first official telephone was invented in 1876. It was Alexander Graham Bell who really started telephone technology development. After the first functional telephone, development has been very fast. Soon telephones spread from America to Europe. Finland has been one of the leading countries in the telephones development. Daniel Johannes Wadén has been called the pioneer of Finnish telephone technology. Wadén worked with the Swedish telephone company, L M Ericsson, and he created the L M Ericsson's subsidiary in Finland. L M Ericsson became the largest and most comprehensive telephone equipment and spare parts seller. The subject of the thesis is a wall telephone manufactured by LM Ericsson in the year 1897. The thesis is based on giving the wall telephone a unified look. The work has focused on the wall telephone’s materials and working methods. The thesis also includes in-formation about the wall telephone’s operating techniques. The research section de-scribes the telephone and telephone exchange history and the telephone’s arrival in Finland. The thesis also includes dokumentation of the wall telephone, the restoration plan, and a report of the restoration. The wall telephone will be placed an individual home. The wall telephone will be indoors, so it must be cleaned with care. With so many materials, the cleaning and working methods took very long time. The areas suffering the greatest damage were the wall telephone’s surface and its metal parts. It also has a few missing parts, which have been made and ordered to complete the wall telephone’s integrity.