Thanks for your help. I did look at that thread, but it seemed like this was a step further into the process and people were looking for a solution to interference.
Let me check I have this correct:
There is 1 USB output on the back of the Grid. Usually this would be plugged into (say) Ansible, which would provide power via the 5v rail. This (sometimes? always?) causes unwanted noise and so a Y-splitter cable is required to isolate the power from the data - with the power being provided by a separate 5v charger, as depicted in this post - Ansible & grid / power issues?
Furthermore, in the case of the Teletype, it’s not just that there could be interference but also that the Teletype could let too much power through from the 5v rail which could fry the Teletype or Grid in certain circumstances?
So the linked solution with the Y-cable would be a safe option for connecting the Grid to either Ansible or Teletype?