Wir haben dieses sehr hübsche und recht rare Pong im Vollmetallgehäuse kürzlich bei Ebay erstanden. Danke dafür an Dirk Seherr! Es handelt sich wahrscheinlich um einen Bausatz. Bitte Bilder anklicken für vergrösserte Darstellung.

Screenshot - Nur ein Spiel ist "eingebaut":

Die Technik:

David Winter von Pong-Story (Frankreich) meint dazu (in englisch):

This is the TV Tennis kit from the Elektor article published in Nov 1975: Elektor Kits.
Some extensions were also made later in 1976 to add sound and scoring.

I think it was sold as a kit. I'm not sure if it is analog or digital, it depends how the various functions communicate together.
If the signals between them is TTL (binary in the form of, for example 0V and 5V) then you can consider it digital.
If the signals are analog, then it's analog. Only the schematics can tell you, I'll check this.

5 minutes later...

I checked the schematics quickly, in fact the design is mostly digital. There may be some very small parts using analog signals but I'm not sure. Everything is made using flip-flops, NAND and other logic gates. The article on my site will show you the extension that you could build back them, like scoring, sound and automatic serve.

Jens Brinkmann hat uns diesen Scan einer Bausatz Werbung geschickt, die er aus einer ELO (Elektronik fuer Praxis und Hobby) Zeitschrift entnahm (Ausgabe October 1976):