The Odyssey 400 dedicated console was released in 1976. The 400 is essentially the same as the Odyssey 200 with automatic serve and on-screen digital scoring features added. The console plays the same three games as the 200 and has the same three game control knobs. An additional Texas Instruments chip was used to implement on-screen scoring.
Source: Wikipedia, "[en.wikipedia.org/wiki/Magnavox_Odyssey_series%23Odyssey_400 Magnavox Odyssey series]", available under the CC-BY-SA License.