This article explores the history of the Tibetan and Mongolian Morse codes, devised by the Nationalist government between 1934 and 1937, by situating them within the infrastructural and political transformations that took place in China and Tibet during these four years. On the one hand, it demonstrates that the engineering of Tibetan and Mongolian Morse codes coincided with the global emergence of shortwave radio telegraphy which, for the first time, enabled communications between geographically distinct regions, such as Tibet and China. On the other hand, it also shows that the codes were devised at a critical political moment in Sino-Tibetan relations: with the death of the Thirteenth Dalai Lama in 1933 and the subsequent political ascendance of the Ninth Panchen Lama, the government believed that the Tibetan and Mongolian Morse codes would help the party rule over the Buddhist frontiers through an alliance with the Ninth Panchen Lama. This plan ultimately failed, as the Panchen Lama died in 1937, before he could take control of Tibet. In short, the government-funded coding project offers a lens into pondering the infrastructural politics of state-building in China.