There's an art project from a few years ago which made a feature of running Strowger switches. The art aspect deals with migration and conflict minerals. http:

There's an art project from a few years ago which made a feature of running Strowger switches. The art aspect deals with migration and conflict minerals. http://yoha.co.uk/tantalum http://yoha.co.uk/tantalum "The first thing that visitors see is a towering rack consisting of electromagnetic Strowger telephony switches. The undertaker Almon Brown Strowger patented this design in 1891, the first automated telephone system of its kind. The switches are triggered by a computer..."