# WhatIsSMS.com Documentation

> The Global Authority on Mobile Messaging Technology. A volunteer-driven knowledge hub for developers, marketers, and telecom engineers.

## Site Overview
WhatIsSMS.com provides comprehensive technical documentation, business guides, and developer tools for the mobile messaging ecosystem (SMS, MMS, RCS).

## Core Knowledge Base

### Technical Protocols
- [What is SMS?](https://whatissms.com/what-is-sms) - Deep dive into SS7 signaling, PDU architecture, and history.
- [GSM-7 vs Unicode](https://whatissms.com/gsm7-vs-unicode-sms) - Character encoding standards, 7-bit packing, and segment calculation logic.
- [SMS vs MMS vs RCS](https://whatissms.com/sms-vs-mms-rcs) - Protocol comparison, throughput analysis, and device support.
- [Does SMS Require Internet?](https://whatissms.com/does-sms-require-internet) - Analysis of cellular signaling channels vs IP-based messaging.

### Business & Infrastructure
- [What is A2P SMS?](https://whatissms.com/what-is-a2p-sms) - Application-to-Person messaging architecture and routing.
- [What is 10DLC?](https://whatissms.com/what-is-10dlc) - US carrier regulations for 10-Digit Long Code business messaging.
- [What is a Short Code?](https://whatissms.com/what-is-short-code) - Dedicated vs shared codes, throughput tiers, and provisioning.
- [Bulk SMS Guide](https://whatissms.com/what-is-bulk-sms) - Infrastructure for high-volume messaging.

### Security & Compliance
- [Smishing Defense](https://whatissms.com/what-is-smishing) - Analyzing SMS phishing vectors and network-level protection.
- [SMS Marketing Best Practices](https://whatissms.com/best-sms-marketing-practices-2026) - TCPA/GDPR compliance, opt-in/opt-out management.

## Developer Tools
Interactive tools running client-side for debugging and optimization:

- [SMS Segment Calculator](https://whatissms.com/tools#character-counter) - Logic to calculate message segments based on GSM/Unicode charset detection.
- [SMS PDU Decoder](https://whatissms.com/tools#pdu-decoder) - Tool to parse raw Hex PDU strings into readable JSON (SMSC, OA, SCTS, UD).
- [SMPP Log Analyzer](https://whatissms.com/tools#smpp-analyzer) - Parser for standard SMPP protocol logs (bind, submit_sm, deliver_sm).

## Community
- [About Us](https://whatissms.com/about) - We are an open-source collective democratizing telecom knowledge.
- Contact: info@whatissms.com