To communicate effectively, especially in a business, it's vital to grasp the technical elements of text SMS components. Here's an in-depth look at each part of a text SMS:
1. Header (Sender ID)
Structure: The sender ID can either be numeric or alphanumeric.
Numeric Sender ID: Typically a phone number like "1234567890".
Alphanumeric Sender ID: Up to 11 characters long, combining letters and numbers for branding like "AMAZON".
Registration: Various regions, like in India, require businesses to register sender IDs to prevent spam and establish authenticity.
Character Limit: Alphanumeric sender IDs are limited to 11 characters, including spaces and special symbols.
2. Message Body
Character Limit:
Standard SMS: Capped at 160 characters; exceeding this limit splits the message into multiple parts.
Concatenated SMS: Longer messages are divided into separate SMS portions and reassembled by the recipient's device. Each portion typically allows 153 characters to include the necessary metadata.
Encoding:
GSM 7-bit: Common encoding allowing 160 characters per message.
UCS-2: Used for non-Latin languages, granting 70 characters per message.
Segments: Lengthy messages are segmented into 153 (GSM 7-bit) or 67 (UCS-2) character parts, each with headers for reassembly.
3. Footer
Character Limit: Falls within the 160-character SMS cap, with footers included in segmented messages.
Opt-Out Mechanism: Crucial for compliance with laws like GDPR and TRAI, providing recipients an option to unsubscribe.
4. Time and Date Stamp
Automatic Generation: Timestamps are added automatically by the SMS service provider.
Structure: Typically includes both date and time, aligned with the sender's time zone or UTC.
5. Unique Identifiers (Optional)
Personalization: Enhances personalization and security.
Dynamic Content: Inserts dynamic elements like transaction IDs and personalized greetings using placeholders in SMS templates.
Technical Protocols and Considerations
SMPP (Short Message Peer-to-Peer Protocol): Utilized in the telecom sector to exchange SMS messages between entities.
HTTP/S API: SMS gateways offer APIs for message sending, facilitating web application integration.
Delivery Reports (DLR): Carriers send DLR to confirm message delivery, including status and timestamp information.
Compliance and Regulatory Requirements
DND (Do Not Disturb) Lists: Companies must comply with regulations concerning DND lists; for instance, TRAI mandates consent before sending messages.
Content Filtering: Some gateways employ content filtering to block non-compliant messages before transmission.
Security
Encryption: Messages are often encrypted during transit for safeguarding sensitive data.
Two-Factor Authentication (2FA): SMS is commonly used for 2FA, demanding secure handling of OTPs and other sensitive information.
Understanding these technical aspects enables companies to craft, dispatch, and oversee SMS communications effectively, ensuring reliability, compliance, and security.