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Taken from Wiki:


* MM1 — the 3GPP interface between MMS User Agent and MMS Center
* MM2 — the 3GPP interface between MMS Relay and MMS Server
* MM3 — the 3GPP interface between MMS Center and external servers
* MM4 — the 3GPP interface between MMS Centers
* MM5 — the 3GPP interface between MMS Center and HLR
* MM6 — the 3GPP interface between MMS Center and user databases
* MM7 — the 3GPP interface between MMS VAS applications and MMS Center
* MM8 — the 3GPP interface between MMS Center and the billing systems
* MM9 — the 3GPP interface between MMS Center and an online charging system
* MM10 — the 3GPP interface between MMS Center and a message service control function
* MM11 — the 3GPP interface between MMS Center and an external transcoder
 
Some sites ( http://imodzone.net/forums/lofiversion/index.php/t162724.html ) are advertising that the iPhone 3GS has MMS23 while the 3G only has straight MMS - have seen this on more than one site so I don't think it's a typo. I have Googled MMS23 but can't seem to find an explanation. Does anyone know what this is and what makes it different from plain MMS?

My assumption is that the original poster of those threads copied and pasted that text from Apple's website, where the 23 would refer to a callout at the bottom of the page. They must've missed removing it before posting.
 
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