The first originally developed Soviet machine gun was the 7.62mm FP (Degtyarev Pekhotny, i.e. Infantry), which appeared in 1926.
The DP was the first of a series of Degtyarev machine guns adopted by the Soviet Union.
A tank version called DT (Degtyarev Tankovy) may still be found on older Soviet armored vehicles in use among Ex-Soviet allies and the third world countries.
Photos 2 & 3: MKFI @ Wikimedia Commons
Photographed in the "Winter War - 70 years" exhibition in the Military Museum of Finland