From Newsgroup: comp.mobile.ipad
How to Enable RCS on iPhone with iOS 18
https://www.androidauthority.com/how-to-enable-rcs-messaging-on-iphone-to-text-android-users-3482571/#2
Fundamentally iMessage is an internet-based service that delivers your
messages via Apple's servers which means it doesn't work most of the time unless you have all the myriad requirements (and which is why most of the
world shuns Apple devices as only working in the richest countries).
RCS, on the other hand, is a carrier-based service and works everywhere the carrier supports it (without needing the net just to do anything useful).
In other words, if you want it to work, don't use the Apple walled garden.
Worse, the article explains that Apple (again!) murdered privacy, saying:
"Apple warns that user identifiers are exchanged for your carrier
and their partners to authenticate your device and provide a
connection for RCS messaging. "These identifiers could include
but are not limited to your IMEI, IMSI, current IP address,
and phone number. Your current IP address might also be shared
with other RCS users," the company notes."
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Apple mostly sells to people who do not understand the technology.
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