Why do I need Cellular Data turned on to send/receive MMS?

basil1091 wrote:

HOWEVER, that all said, I currently have my cellular off, and was just texting with 2 iphones, multi person text and received pictures. So maybe something changed with an update??

No, nothing has changed. For MMS, you need celluar data. However, you can send pictures over iMessage using WiFi.

Then my cellular data is on, even though I have it turned off and if that's the fact, that's a HUGE issue. I was using MMS and am 100% sure it was off. Funny thing too, once I start squawking about things like this, they usually stop happening...big brother is watching!!

Facebook messenger sends pics through wifi (no data needed). It's a little annoying not being able to do it straight through texting, but it saves data. (unless of course the recipient has imessage...then I use imessage)

I don't understand why so many people have trouble getting this, so I'm going to explain it in detail.

There are TWO basic services that your phone uses over cellular:

- Voice

- Data.

When you call someone, you are obviously using voice. However, what most people don't realize is that when you text someone, from the network's perspective you are sending a different kind of "call", delivering the text message to their phone. This is why text messages are limited to 160 characters; they are transmitted through the call setup/signalling channel which is extremely bandwidth-limited.

Data is entirely different. In order to transmit information that is not an SMS or a voice call, your phone has to use the data network. There have been several data networks in the history of cellular communications (GPRS, EDGE, etc.) but they all do the same thing.

Data over cellular is transmitted through a router called an APN, or "Access Point Name". There can be different APN's for different types of data service. For example, a provider might have:

- WAP APN, used for browsing the web from a cellular phone, with proxies to reduce bandwidth use. Most providers don't use this anymore since smart phones can handle the "full internet" so to speak.

- ISP APN, used for general Internet access, such as a smart phone, or when you tether.

- MMS APN, used for transmitting MMS messages.

See that last one? MMS messages still use your data connection, but they go through a different APN. This is why your provider doesn't deduct them from your data plan. But you STILL need to have cellular data turned on because it's.. well, data (image data, and MMS texts longer than 160 characters) and you can't send that stuff over the signaling channel above.

And you can't send MMS over WiFi because the MMS APN is simply *not reachable* from anywhere other than the provider's cellular network.

It really is that simple. Apple isn't trying to pull one over on you, nor is your provider. The ONLY thing that can be physically sent without cellular data turned on are SMS messages and voice calls. PERIOD.

I hope this makes some sense of this for folks who are still confused. 🙂

Yes that all makes sense, however, I did receive a picture message while texting with 2 other people in a group message who both have Iphones, while my cellular data was OFF. So I don't know what's going on. Also, as someone pointed out, you can transmit a picture up to Facebook without having cellular on. Why does that differ from sending it through a text?

Ok so first make sure you have iMessage, group messaging, and the "send as SMS when iMessage is not available" preference on. Now there are different problems everyone has with this.

1. I have wifi connection but I am unable to receive/send group messages (photos or just plain texts).

-ok so I had this same problem and today I turned on my cellular data and I got a whole bunch of messages from a group of friends all at once. My friend called me before that and asked me why I hadn't been texting them and I didn't know what he was talking about since i hadn't gotten any messages all day from them. Anyway, so the reason why you aren't receiving those group messages is because group messages require MMS which doesn't work unless you have cellular data turned on. That makes me mad because I would like to be able to receive messages on a daily basis without having to turn on cellular data to make sure I get all my messages!

-thats what I have gotten from other comments and personal experience so I hope this works for you and if it doesn't then I'm sorry and I wish you good luck!

~emily4dice

MMS is entirely a carrier service. SMS messages use the voice signaling channel, so they only require that your phone be able to make phone calls. SMS is limited to 160 bytes, not enough to send an image, so for anything with an attachment it must use MMS, which uses the carrier's cellular data channel for the attachments. The cellular carrier's network does not "know" anything about your WiFi connection, so it can't use it. All it knows is the carrier's services. This is also true for Visual Voicemail; again the carrier only knows about the cellular network data channel; it does not know your WiFi connection exists.

If all of your friends have iPhones then your multimedia messages can use iMessage, which WILL work over WiFi.

I found this thread trying to figure out how to keep my cellular down with iOS 8. I would sit right in front of my Wifi and it would go to cellular (explained above). I had cellular off but then I CANNOT send an MMS or text an email address that is also an iPhone.

I just turned cellular on but turned it off for every app I have. I have also turned off Background Refresh. I'll track my Cellular usage.

Question: If I have cellular turned on, will it use that for SMS or will it use Wifi?

If you send an SMS or MMS it will use Cellular because those 2 are carrier services. They cannot go out through anything but the carrier network.

If you send an iMessage it can use either Cellular or Wifi. But if connected to Wifi it should use Wifi.

That's not possible. SMS and MMS are carrier services, they simply cannot use Wifi in any way. Whatever you were sending tthrough wifi were not SMS.

In the Messages App. If the message being sent turns green its an SMS and is not going through Wifi. Its going to the carrier netwpork and using your Text Message quota. if its Blue its an iMessage and will go out through Wifi if available.

I have my cellular off and I am able to text. I just sent a text to a friend on an iPhone and someone with an Android. The iPhone message is green and went through and the other is blue and went through. I cannot send an MMS to the iPhone without Cellular but I did just send one to the Android

I'm thinking because it's an iPhone that is different. I'm clearly not technical, just telling you what is going on on my phone.

SMS text messages (Green bubble) use the cell voice system, not cell data, and turning cell data off will not affect them. Put your iPhone in Airplane mode, turn WiFi on and try to text a friend with an Android phone.

I don't care that much. I was trying to understand how this all works so I don't go over my cellular usage. All I do know for sure is that I cannot send a photo to my friend with the iPhone without cellular on.

This has been helpful but it'll take awhile for it to sink in. I can read it 20 times and still not remember it.

Thanks all

Hi,

The strange this is that other phones (HTC, aso) does not need an active connection when you receive a mms. It automatically turns data network on when you get a MMS.

For people without unlimited data and occasional need for data network the workaround with turning off data for specific programs is too difficult for a simple user.

Is there another way?

"It is what it is".. you see this kind of response is one the reasons why for some people, anything having to do with apple products leaves a bad taste in their mouth. "You want to use MMS? Then you need cellular data turned on. Turn it off...no MMS." Whether or not your statement is correct is not the point. The point is that I would have thought being such a helpful little Level 10 on the apple community forums, in which apple themselves do not contribute any content, that you might have at least tried to answer someones question without the condescension inherent in telling a grown man "it is what it is" and then following that with "you want MMS?" as if you might take it away for misbehaving. Maybe you didn't mean it like that but when I glance up at your current picture and look at the guy showing the world how cool he is smoking a cigarette with shirt open... I think that alone sums it up better than words ever could. The man asked a valid question to which you responded is as dismissive a way possible.