No, it is the WPS button. One would use the REMOTE CONTROL ports to connect to and control, or be controlled, by the Marantz Model 10.
Some might want to combine the Marantz Link 10n, Marantz Model 10 and Marantz SACD 10 into their ultimate two channel system but will find it very limited for a very ridiculous amount of money.
The Marantz Link 10n is the only one of the three with a sub pre out. The SACD 10 is a two channel affair with no HDMI or 5.1 analog outputs. The Model 10 can control one or the other but not both as it has but one REMOTE CONTROL output..
Had the SACD 10 been equipped with 5.1 analog out, three Model 10 amps can be linked together to accommodate a 5.1 analog connection for those stupid enough to blow that kind of money.
If one connects a Link 10n to a TV to use ARC and also connects to the Model 10 for power, the REMOTE CONTROL port of the Link 10n be set to INTERNAL and the Model 10 to EXTERNAL.
If no TV is involved and connected to the Link 10n, the Model 10 REMOTE CONTROL setting of the Model 10 can be set to INTERNAL and the Link 10n or SACD 10 can be set to EXTERNAL and be controlled by the Model 10 remote controller.
One could also just buy the Marantz AMP 20 and AV 20 combo for less money and more functionality and connect them to any moderately priced streamer and SACD player.
Of course, those wanting to save even more money but stay with Marantz could go for a Cinema 30 and use built in HEOS streaming functionality and still manage to sleep the sleep of the just.
Those with big wallets and little d#%ks can still opt for the Marantz Link 10n, SACD 10 and Marantz Model 10.