Can you please clarify your inquiry? What Onn Roku device are you trying to pair? Roku devices in general do not pair to each other aside from a Roku device/TV and Roku audio products (streambar/soundbar/wireless speakers).
With more information we will be able to assist you further.
If you mean pairing the remote from an Onn Roku TV with a TCL Roku TV and another Roku player, the answer is likely no. The TV remotes are likely just IR. Different manufacturers use different IR codes, so the Onn Roku TV remote likely won't work for the TCL TV. I say likely because some manufacturers do use the same codes. My Sharp Roku TV remote will control a Vizio TV I have in the same room, so I have to cover the Vizio IR receiver window.
IR remotes do not require "pairing". If the remote is using the proper IR codes, it just works. No pairing needed or possible.
And my Sharp Roku TV remote (IR only) does not seem to do anything to my Roku Premiere that's in the same room, so it also appears that Roku players use different IR codes from Roku TVs.
Finally, if the Roku player is a Stick, it only works with WiFi Direct remotes. It does not have IR functionality at all.
If for some reason you have a WiFi Direct remote, I believe a device can have more than one remote paired at one time. But I'm not certain if one remote can be paired with multiple TVs.
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