Device for unprofitable duplex telegraphs

A device for unprofitable duplex telegraphs: No. 28029. Supponent.04/29/1909.Issues on 08/31/1915 / "Marconi, a company of unprofitable telegraphs."- [B.m .: B. and., 1915].-3 p., 1 l.Il .. -Description of the device for unprofitable duplex telegraphs, in which the transmitter and receiver alternate in a quick sequence are put in the current position and removed from the latter.To the privilege of the British company of the unprofitable telegraph of Marconi, with limited liability (Marconi's Wireless Telegraph C ° Ltd), in London, declared on April 29, 1909 (og. St. No. 39376).Class 21a.No. 28029. The privilege issued on August 31, 1915.Ex.: With a handle.litter..I. "Marconi", a company of unprofitable telegraph with limited liability (London) .1.People (collection).Electronic copy source: PBOriginal storage location: VPTB FIPS