Nathan wrote: "Since implementing S/S in the U.S. requires a 499 Filer ID, it is actually kind of infuriating that the RMD does not have 499 Filer ID as a required field on their form. That would nip this issue right in the bud if they did." Yes, that would be a good idea. Generally it is easier to get a 499A Filer ID than it is an OCN. The good news is that in their Sixth Report and Order (https://docs.fcc.gov/public/attachments/FCC-23-18A1.pdf) the FCC wrote, at paragraph 48: "Finally, we require filers to submit their OCN if they have one. An OCN is a prerequisite to obtaining an SPC token, and we conclude that filing the OCN or indicating that they do not have one will allow us to more easily determine whether a provider is meeting its requirement to diligently pursue obtaining a token in order to authenticate their own calls and provides an additional way to determine relationships among providers." Presumably they will implement this shortly (the Order is pending some administrative reviews).