This is a typical system using catridges based on the different chipsets developped by General Instruments in the late 70s. Each GI chips was able to generate several games, ball games for a start, then later car racing, motorcycle, submarines, tanks and shooting games.
The system has two detachable controllers with one analog joystick and one fire button each. The control panel is composed of 10 buttons to select the different games offered by each cartridge (10 being the maximum). Difficulty switches, power switch, service auto/manual switch and a start button can also be found.
Hopefully there's even a volume control slider, which is VERY useful as the sound coming of this console is quite irritating.
This particular model was apparently designed by Soundic in Hong-Kong and then sold to many companies worldwide so they could market the system under their own brand. That's why the SD-070 console can be found under many different brands. Case design may vary but inside it is always the same motherboard. The electronic board of the one we have opened is labeled "SD-70S Rev. 4", S surely stands for SECAM (we had a french model). There were also SD-050 and SD-090 models, all compatible with each others, i.e. using PC-50x cartridges.