| Radios | ||
| introduced 1920/21 |  |
|
| introduced 1921/22 | ||
| introduced 1922/23 | ||
| introduced 1923/24 | ||
| introduced 1924/25 | ||
| introduced 1925/26 | ||
| introduced 1926/27 | ||
| introduced 1927/28 | ||
| introduced 1928/29 | ||
| introduced 1929/30 | ||
|
Nauen -- Telefunken - high - power radio station |
