Why is my s7 converting sms to mms and can I stop it from sending mms?

It randomly converts smsto MMS but does not warn me. I am therefore being billed by my supplier.

I don't think it's random, rather the message length. You should take a look. Once it reaches 450 characters its automatically converted. You may want to download a third party app that doesn't convert automatically.

chanchan, that's 160 characters in ASCII, 80 in Unicode. Most of them can be told either to not convert to MMS, or to break long texts up (same thing). A text can, by definition, be only 140 octets long (which is 160 ASCII characters), so if it's longer than that, the entire message gets converted to a text file that goes by MMS, or it gets chopped into multiple 140 octet pieces. (There's no third way, except 3rd party apps that can handle longer texts - but both people have to be using the same app.)

Originally Posted by Rukbat

chanchan, that's 160 characters in ASCII, 80 in Unicode. Most of them can be told either to not convert to MMS, or to break long texts up (same thing). A text can, by definition, be only 140 octets long (which is 160 ASCII characters), so if it's longer than that, the entire message gets converted to a text file that goes by MMS, or it gets chopped into multiple 140 octet pieces. (There's no third way, except 3rd party apps that can handle longer texts - but both people have to be using the same app.)

Uh no. The Samsung app supports 450 characters, also known as a 3 part message. And I've sent a 3500 character text (23 oart message) to an iPhone via chompSMS and she received it properly and I know it's SMS because not only do I have MMS disabled, MMS is not often popular in my country and is almost always disabled on my phones. I've also send 1000 character messages to Android and they received it as SMS. You are not limited by the 150 SMS character limit. The app itself will string each SMS together as a 3 part message or longer. The receiving phone will then string it together to form one single message as well. Or if the phone is old, you send one message, the recipient gets it in multiple parts. My Galaxy Fit and Galaxy S receives broken down messages. My more recent phonrs (Note 2 and S7 Edge) strings them together. The stocl Samsung app only connects 3 part messages. Using a third party messaging app like chomp or textra, you can tell it to not change to MMS.

ChompSMS may (I don't run it so I don't know) use a proprietary format. (If both ends need the same "sms" app, it does.) Apple does. However, SMS, as detailed in RFC 5724, specifies:

"GSM SMS messages are alphanumeric paging messages that can be sent to and from SMS clients. SMS messages have a maximum length of 160 characters (7-bit characters from the GSM character set [SMS-CHAR]), or 140 octets. Other character sets (such as UCS-2 16-bit characters, resulting in 70-character messages) MAY also be supported [SMS-CHAR], but are defined as being optional by the SMS specification."

And the RFC is always the final word.

Uh no again. You're talking about one single SMS. A long SMS like what I'm talking about is called a concatenated SMS. Basically the app allows you to string together multiple SMS into one whole part. It can be as long as 255 SMS long. Each SMS is sent as a 7 bit file with a header saying which part of the SMS it is. Mobile phones have been using this since 2000s. My old 3310 can send and receive a 5 part SMS (450 characters) as one message. It's not a proprietary format. It's been a standard for so many years already. Unless your carrier is stuck on 90s tech, your phone can receive and send long SMS greater than 140 characrers, limited only in sending by how many the app that is sending allows, since the tech limit is 255 parts.

So SMS is 160 characters.

Multi-part SMS is a thing. 153 characters per part, since space is being used to tell the recipient that there's more.

Some phones and/or SMS clients might not be able to handle that - as in if you type 161 characters, it may just convert it to MMS so that it sends as one message or it'll be broken up into one 153 character message and one 8 character message. The phone receiving the message may be able to combine the message back to look like one complete 161 character message, but to the carrier, it will still count as 2 SMS messages.

Originally Posted by AC Question

It randomly converts smsto MMS but does not warn me. I am therefore being billed by my supplier.

Which specific Galaxy S7 model are you using?

What carrier at you using the S7 on?

What app are you using for SMS/MMS?

Originally Posted by Ry

Which specific Galaxy S7 model are you using?

What carrier at you using the S7 on?

What app are you using for SMS/MMS?

On my Galaxy S7, the stock SMS app can send SMS as long as 3 parts before being automatically converted to MMS. This is a Southeast Asian Dual SIM variant.

The longest I've sent is a 23 part SMS on chomp. I know Textra can support at least 7 parts (haven't tried longer than that yet but I think thay can do 20+ since they have same devs as Chomp), and EvolveSMS can do at least 10 parts.

Originally Posted by chanchan05

On my Galaxy S7, the stock SMS app can send SMS as long as 3 parts before being automatically converted to MMS. This is a Southeast Asian Dual SIM variant.

The longest I've sent is a 23 part SMS on chomp. I know Textra can support at least 7 parts (haven't tried longer than that yet but I think thay can do 20+ since they have same devs as Chomp), and EvolveSMS can do at least 10 parts.

This could vary from S7 to S7.

Any fix for this?

Check the settings in your SMS app.
The good apps let you choose between converting long SMS to MMS and breaking up the long message into pieces.

If you need a better SMS app than you have, Textra and Chomp are good alternatives as are the other apps mentioned above.