Modern phones support several types of text messaging. While sending a message looks simple, different technologies (SMS, MMS, and RCS) may be used behind the scenes, and behaviour can vary between Android phones, iPhones, and mobile carriers. This guide explains the essentials.
1. SMS — the original text message
SMS (Short Message Service) is the traditional text-only message system:
- Works on all mobile phones
- Uses the mobile network (no internet required)
- Typically limited to 160 characters per message segment
If you send a longer message, your phone normally splits it into multiple SMS segments automatically and the receiving phone usually reassembles them so the message appears as one. You normally do not need to manage this yourself.
2. MMS — messages with photos and group texts
MMS (Multimedia Messaging Service) is used when:
- Sending photos or videos
- Sending audio clips
- Sending many group messages
- Sending certain longer formatted texts
MMS uses mobile data rather than the voice/SMS signalling channel and may be slower. Some carriers also set limits on attachment size.
3. RCS — the modern messaging standard
RCS (Rich Communication Services) is a newer messaging system designed to replace SMS/MMS with features similar to internet messaging apps.
Typical RCS features include:
- Typing indicators
- Read receipts
- High-quality photo sharing
- Improved group chats
- Message delivery confirmation
- End-to-end encryption (in some cases)
RCS operates over the internet connection (mobile data or Wi-Fi).
The “Universal Profile”
To ensure compatibility between networks and devices, carriers and device makers developed a common standard called the RCS Universal Profile. Phones and networks that support this profile are more likely to interoperate correctly.
Fallback behaviour
If either the sender or recipient does not support RCS — for example:
- Messaging between Android and older phones
- Messaging where the carrier does not support RCS
- Messaging between Android and some non-RCS devices
the phone automatically falls back to SMS or MMS, ensuring the message is still delivered.
4. Encryption considerations
Some messaging systems (for example, iMessage between Apple devices or certain Android RCS implementations) can provide end-to-end encryption. However:
- Encryption usually works only when both sender and recipient use the same compatible messaging system
- Messages sent across platforms (for example Android ↔ iPhone using SMS/MMS) are typically not end-to-end encrypted
- When fallback to SMS/MMS occurs, encryption is generally lost
This is normal behaviour and depends on compatibility rather than user error.
5. Forwarding a message
Forwarding lets you send a received message to another person.
Android (typical):
- Open the conversation
- Long-press the message
- Tap Forward
- Choose recipient and send
iPhone (typical):
- Tap and hold the message
- Select More…
- Tap the forward arrow
- Choose recipient and send
Recipients usually receive the text as a normal message, sometimes with “Fwd:” added automatically.
6. Sending messages to multiple recipients (group messaging)
When composing a message, you can add multiple recipients. Depending on phone settings, messaging app, and carrier configuration, two behaviours are possible:
Group conversation
- Everyone receives replies from all participants
- Similar to “Reply all” in email
- Often uses MMS or RCS
Individual replies
- Each recipient receives the message separately
- Replies return only to the sender
Because behaviour varies, avoid sending private information in group texts unless you understand how your phone handles replies.
7. Differences between Android, iPhone, and carriers
Most messaging features are similar across devices, but differences can occur due to:
- Phone platform (Android vs iPhone)
- Messaging app used
- Carrier network capabilities
- RCS support availability
- MMS attachment limits set by carriers
For example, a conversation may use RCS between two compatible Android phones but automatically fall back to SMS/MMS when messaging an iPhone or a device without RCS support.
8. Practical tips
- If you want more message options, try long-pressing the message.
- Long messages are usually handled automatically; phones split and reassemble them.
- Photos and many group messages use MMS or RCS.
- If advanced features disappear in a conversation, the phone may have fallen back to SMS/MMS because the other device or carrier does not support RCS.
Tech Café takeaway:
Understanding whether a message is using SMS, MMS, or RCS explains why some conversations support read receipts, typing indicators, or encryption — and why these features sometimes disappear when messaging different types of phones.