The codes do not exist for the tape deck alone. You will not be able to control it without an Onkyo/Integra receiver connected to it via RI cable (Remote Interactive). The receiver gets the commands and translates them for the deck to use.
There were a handful of Onkyo decks in the 80s that used an actual remote but I'd say not for at least the past 10-15 years.
Now, if you have an Onkyo receiver, connect the RI cable and the transport buttons on the OEM remote will run the deck. You may have to learn them into another remote you are using.
There is no truth anymore. Only assertions. The internet world has no interest in truth, only vindication for preconceived assumptions.
