DialNext

Tag: SMS Delivery

  • What Are Unicode SMS and GSM Encoding?

    What Are Unicode SMS and GSM Encoding?

    SMS Encoding determines how characters inside a text message are converted and transmitted across mobile networks. Different encoding formats affect which characters you can use and how many characters fit inside a single SMS segment.

    Understanding Unicode SMS and GSM encoding helps businesses avoid unexpected message splitting, higher SMS usage, and formatting issues when sending messages at scale.

    Why Does SMS Encoding Matter?

    Every SMS message has a character limit. However, that limit changes depending on the characters used inside the message.

    For example, a simple English text message usually supports more characters than a message containing emojis or certain special characters.

    SMS Encoding helps determine:

    • How messages are processed
    • How many SMS segments are created
    • Which characters are supported
    • How messages appear on customer devices

    As a result, businesses can better manage messaging costs and customer experience.

    What Is GSM Encoding?

    GSM encoding, also called GSM-7, is the standard character set used for most SMS messages.

    It supports common characters such as:

    • English letters
    • Numbers
    • Basic punctuation
    • Common symbols

    A single GSM encoded SMS message supports up to 160 characters.

    Examples:

    Hello, your appointment is confirmed for tomorrow.

    Your verification code is 482931.

    Since these messages only contain GSM-supported characters, they can use the full SMS character limit.

    What Is Unicode SMS?

    Unicode SMS uses a broader character set that supports languages and symbols outside GSM encoding.

    Unicode allows messages to include:

    • Emojis
    • Non-Latin languages
    • Special symbols
    • International characters

    Examples include:

    • Chinese
    • Japanese
    • Arabic
    • Hindi
    • Emoji characters

    However, Unicode messages have a smaller character limit because each character requires more data.

    A single Unicode SMS message supports up to 70 characters.

    GSM vs Unicode SMS

    Although both formats deliver text messages, they have different limits.

    GSM EncodingUnicode SMS
    Supports standard charactersSupports global characters
    Up to 160 characters per SMSUp to 70 characters per SMS
    Smaller message sizeLarger message size
    Common for English messagesRequired for emojis and many languages

    Choosing the correct format helps prevent unexpected SMS segmentation.

    What Are SMS Segments?

    When a message exceeds the character limit, mobile networks split it into multiple SMS segments.

    For longer messages:

    • GSM messages usually allow 153 characters per segment.
    • Unicode messages usually allow 67 characters per segment.

    The recipient still sees one complete message, but multiple SMS segments may be used behind the scenes.

    Common Characters That Trigger Unicode SMS

    Some characters may automatically convert a message from GSM to Unicode.

    Examples include:

    • Emojis 😊
    • Curly quotation marks “ ”
    • Certain accented characters
    • Non-English alphabets
    • Special symbols

    Before sending large campaigns, always check whether your message uses Unicode characters.

    How to Reduce SMS Segments

    Businesses can optimize messages by following a few simple practices.

    We recommend:

    • Remove unnecessary emojis.
    • Replace special quotation marks with standard quotes.
    • Keep messages short and clear.
    • Test messages before sending campaigns.
    • Use SMS optimization tools when available.

    Additionally, reviewing message length before sending can help control costs.

    Does DialNext Support SMS Encoding Optimization?

    Yes. DialNext automatically manages SMS Encoding to help improve message compatibility and delivery.

    DialNext detects message formatting and helps businesses send reliable SMS conversations without manually handling encoding rules.

    This allows teams to focus on customer communication while reducing common formatting problems.

    Frequently Asked Questions

    Why Did My SMS Become Multiple Messages?

    Your SMS may become multiple segments if it exceeds character limits or contains Unicode characters such as emojis or unsupported symbols.

    Are Emojis Supported in SMS?

    Yes. Emojis are supported through Unicode SMS, but they reduce the number of characters available in each message segment.

    Should Businesses Avoid Unicode SMS?

    No. Unicode is important for global communication. However, businesses should understand how it affects message length and usage.

    Does GSM Encoding Support Every Language?

    No. GSM encoding supports a limited character set. Many international languages require Unicode.

    Related Articles

    Additional Resources

    Learn more about GSM SMS character encoding:

    https://www.unicode.org

    Need Help?

    If you have questions about SMS Encoding, message limits, or business messaging, contact us at help@dialnext.io.

  • What Is Carrier Filtering in Messaging?

    What Is Carrier Filtering in Messaging?

    Carrier Filtering is the process mobile carriers use to identify, review, and block messages that may violate messaging rules or appear suspicious. It helps protect users from spam, fraud, phishing, and unwanted text messages.

    Businesses that send SMS messages should understand how Carrier Filtering works because it can affect message delivery and customer communication.

    Why Does Carrier Filtering Happen?

    Mobile carriers process billions of messages every day. To protect recipients, carriers analyze messaging traffic and identify content that may be unwanted or harmful.

    Filtering systems help detect:

    • Spam messages
    • Fraud attempts
    • Phishing links
    • Unapproved marketing campaigns
    • High-risk message patterns
    • Policy violations

    Additionally, carriers use filtering systems to maintain trust across messaging networks.

    How Does Carrier Filtering Work?

    Carrier Filtering uses a combination of automated systems, compliance checks, and network rules to evaluate messages.

    Carriers may review several factors, including:

    • Message content
    • Sender reputation
    • Sending patterns
    • Message volume
    • Links included in messages
    • Recipient complaints
    • Registration status

    If a message triggers filtering rules, the carrier may block it before it reaches the recipient.

    Common Reasons Messages Get Filtered

    Messages can be filtered for many reasons.

    Common causes include:

    Missing Registration Requirements

    Some regions require businesses to register before sending application-to-person (A2P) messages.

    For example, businesses sending SMS messages to users in the United States often need approved A2P 10DLC registration.

    Suspicious Message Content

    Carriers may block messages containing:

    • Misleading information
    • Unclear sender identity
    • Suspicious links
    • Excessive capitalization
    • Unusual formatting

    Therefore, businesses should write clear and transparent messages.

    Public URL Shorteners

    Many carriers discourage public URL shorteners because bad actors frequently use them to hide unsafe destinations.

    Instead, use branded links whenever possible.

    Missing Opt-In Consent

    Recipients should agree to receive messages before a business contacts them.

    A clear opt-in process improves compliance and reduces filtering risk.

    High Complaint Rates

    If many recipients report messages as spam, carriers may reduce trust in future messages from the sender.

    Sending relevant messages only to interested users helps maintain a positive reputation.

    How to Reduce Carrier Filtering

    Although filtering decisions depend on carriers, businesses can follow best practices to improve SMS deliverability.

    We recommend:

    • Register required messaging campaigns
    • Collect proper customer consent
    • Clearly identify your business
    • Avoid misleading content
    • Use branded links
    • Provide opt-out instructions
    • Keep contact lists updated
    • Avoid sending unwanted messages

    Following these practices improves message reliability and customer trust.

    Carrier Filtering and A2P 10DLC

    A2P 10DLC registration helps carriers understand who is sending messages and why messages are being sent.

    Approved registration does not guarantee every SMS will be delivered. However, it helps establish sender legitimacy and reduces the chance of unnecessary filtering.

    Businesses should still follow messaging policies after approval.

    Does Carrier Filtering Mean My Message Failed?

    Not always.

    Some carriers provide filtering errors when a message is blocked, while others may silently filter messages based on their internal systems.

    Delivery behavior depends on:

    • Destination carrier
    • Country regulations
    • Sender reputation
    • Message content
    • Compliance requirements

    Does DialNext Prevent Carrier Filtering?

    DialNext helps businesses send reliable SMS messages by supporting proper messaging practices and compliance workflows.

    However, final delivery decisions are controlled by mobile carriers.

    To improve delivery rates, always follow carrier guidelines, maintain customer consent, and send relevant messages.

    Frequently Asked Questions

    Can Carrier Filtering Be Removed?

    No. Carrier filtering exists to protect users and messaging networks. Following best practices reduces the likelihood of legitimate messages being blocked.

    Why Are My SMS Messages Being Blocked?

    Messages may be blocked due to compliance issues, suspicious content, missing registration, or carrier filtering rules.

    Does A2P 10DLC Stop Carrier Filtering?

    No. A2P 10DLC improves sender verification but does not guarantee delivery of every message.

    Do All Carriers Use the Same Filtering Rules?

    No. Each carrier manages its own filtering systems, which means delivery behavior can vary between networks.

    Related Articles

    Additional Resources

    Learn more about messaging guidelines:

    https://www.ctia.org

    Need Help?

    If you have questions about SMS delivery, carrier filtering, or messaging compliance, contact us at help@dialnext.io.