Terminology » Mobile Communication » SMS vs MMS: Understanding the Key Differences

SMS vs MMS: Understanding the Key Differences

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SMS (Short Message Service) and MMS (Multimedia Messaging Service) are two distinct messaging services widely used on mobile phones and other devices for sending messages and multimedia content. Let’s delve into each and compare their key differences.

SMS (Short Message Service)

SMS, short for Short Message Service, is primarily designed for sending text messages from one mobile device to another or from a mobile device to a computer via email. The maximum size of an SMS message usually adheres to one of the following limits:

  • 160 characters (7-bit)
  • 140 characters (8-bit)
  • 70 characters (16-bit)

If the recipient’s mobile device is unreachable or switched off, the SMS message is stored in the SMS server (often referred to as the message server) for a duration determined by the message expiry settings configured on the sender’s device. This information is then communicated to the message storage server connected to the network.

Typical SMS settings found on mobile devices include:

Sending Options:

  • Network Selection: Circuit Switch / Packet Switch
  • Character Support: GSM Alphabet / Unicode / Automatic OR Full / Enhanced
  • Relay Path: Yes / No
  • Get Delivery Report: Yes / No
  • Keep a Copy: Yes / No
  • Text Message Center:
    • Text Message Center Number: +919886005444 (Example for Vodafone)
    • Validity Period: None / 1 Hr / 6 Hr / 12 Hr / 1 Day / 3 Days / 1 Week / 1 Month
    • Default Type: Text / Voice / Fax / X.400 / Email / ERMES
    • Name of the Center: SMS Center-1

SMS Protocol Stack Image alt: SMS Protocol Stack

SMS resides within the Connection Management (CM) layer, specifically Layer 3, of the GSM protocol stack. Text or multimedia messages are transmitted from a mobile device to the SMSC (Short Message Service Center), which employs a store-and-forward mechanism. The exchange of SMS/MMS messages between the SMSC and the mobile device (TE - Terminal Equipment) is facilitated by the Mobile Application Part (MAP) of the SS7 protocol. The SMS protocol stack is illustrated in the figure above. Its specifications are outlined in GSM Recommendation 3.40. SMS can also be delivered using the GPRS protocol.

MMS (Multimedia Messaging Service)

MMS, or Multimedia Message Service, enables the transmission of multimedia content such as pictures, videos, and audio. The maximum size of an MMS message is typically around 300KB according to MMS standard 1.2 and approximately 600KB as per MMS standard 1.3.

Similar to SMS, MMS messages can be sent from mobile devices to other mobile devices, to fixed-line telephones with SMS capabilities, or to computers. If the recipient’s device is switched off or unreachable, the MMS message is stored on the MMS server, much like with SMS. Once the network detects that the device is active and reachable, the MMS message is delivered.

Typical MMS settings on mobile devices include:

Sending Options:

  • Priority: Urgent / Normal / Low
  • Expiration: Max / 1 Day / 2 Days / 1 Week / 2 Weeks / Custom Time
  • Delivery Time: Immediately / 1 Hr / 1 Day / 1 Week / Custom Time
  • Get Delivery Report: Yes / No
  • Get Read Report:
  • Keep a Copy: Yes / No

Receiving Options:

  • Home Network: Auto Download / Manual / Reject
  • Foreign Network: Auto Download / Manual / Restricted
  • Send Read Report: Allowed / Never / Always Ask
  • Send Delivery Report: Yes / No
  • Reject Unknown: Yes / No
  • Reject Advertisement: Yes / No
  • Message Size: 30KB / 100KB / 300KB (User-selectable)

SMS vs MMS: Key Differences

ParameterSMSMMS
Full nameShort Message ServiceMultimedia Messaging Service
Type of messagesText-only messagesMessages can include text, images, videos, audio, and more
Message lengthLimited to 160 characters per message in most casesCan be much longer and is typically limited by carrier or device capabilities
Multimedia contentSupports only plain textSupports a wide range of multimedia content, including images, videos, audio, contact cards, and more
Group messagingLimited to sending messages to one recipient at a timeAllows sending messages to multiple recipients or groups simultaneously
CostUsually cheaper than MMSCan be more expensive than SMS due to data usage for multimedia content
Delivery confirmationSupports delivery receipts, indicating if the message was successfully delivered.Supports delivery receipts and read receipts for multimedia content
Internet connection requiredNo, SMS works over the cellular network and doesn’t require an internet connection.May require an internet connection for downloading multimedia content.
CompatibilityCompatible with nearly all mobile phones and devices.Requires a device and carrier that support MMS functionality.
File size limitN/ALimited by carrier and device, but typically larger than SMS.
Use casesCommonly used for simple text messages, alerts, and notifications.Used for sharing multimedia content such as photos, videos, and audio messages.

Conclusion

In summary, SMS (Short Message Service) is a text-based messaging service limited to 160 characters per message, requiring no internet connection. It’s ideal for sending simple text messages and notifications. On the other hand, MMS (Multimedia Messaging Service) enables the transmission of multimedia content, supports longer messages, and may require an internet connection to download and view files. This makes it suitable for sharing rich media content and enhancing communication.