I'm looking at buying another data counter for a pachislo. As far as I know the newer models all use an 8-pin connector and if the data counter has a 6-pin connector it fits fine as well. However, I see several sellers on Yahoo auctions talking about "Units 4, 5 and 6" (after Google translate on their listing).

Does anyone know what is meant by Units 4, 5 and 6? Putting it through a different translator tells me about Models 4, 5 and 6.

The text from the translated auction reads:

All models can be used for Units 4, 5, and 6, but some models have different wiring.
If you contact us in a transaction message with the model you plan to install, we will ship it together with the wiring.
Therefore, even amateurs can easily connect by simply inserting one connector without messing with wiring.
* Please be assured that there are no models that cannot be installed with Units 4, 5, and 6.

Original text:
4・5・6号機には全機種使用可能ですが、配線が異なる機種がございます。
取付予定の機種を取引メッセージにて、ご連絡いただきましたら、配線を合わせて発送いたします。
その為、配線をいじる事なく素人の方でも簡単にコネクタを1本差すのみで接続できます。
※4・5・6号機で取り付けできない機種はありませんので、ご安心ください。