SMS & Telecom Knowledge Base
In-depth guides on SMS infrastructure, carrier filtering, 10DLC registration, TCPA compliance, and programmable telecom for developers and businesses.
SMS & Telecom Knowledge Base
Technical reference guides covering how SMS works at the network level, carrier compliance requirements, and programmable telecom infrastructure.
SMS Infrastructure
| Guide | What You'll Learn |
|---|---|
| How SMS Works | PSTN, SS7, SMSC routing, and how messages travel from phone to phone |
| What Is A2P SMS? | Application-to-person messaging, P2P vs A2P classification, and regulatory treatment |
| What Is 10DLC? | The Campaign Registry, brand/campaign registration, trust scores, and throughput limits |
| Carrier SMS Filtering | How AT&T, Verizon, and T-Mobile analyze and filter SMS traffic |
| Short Code vs 10DLC vs Toll-Free | Comparing SMS sender types: cost, throughput, registration, and use cases |
| TCPA & CTIA Compliance | Federal law, industry policy, consent requirements, and opt-out rules |
| SHAFT+ Restricted Categories | Carrier-restricted content categories and how each layer enforces them |
| SMS Deliverability | Maximizing delivery rates, avoiding filters, and monitoring sender reputation |
Telecom Architecture
| Guide | What You'll Learn |
|---|---|
| CPaaS & Aggregator Stack | The full SMS routing chain from API call to carrier delivery |
| What Is RCS? | Rich Communication Services — how it differs from SMS, carrier adoption, and encryption |
| CALEA & Lawful Intercept | Legal obligations for telecom providers handling voice and messaging |
| Virtual Phone Numbers | How DIDs work, number types, porting, and programmable number management |
x402 Protocol
| Guide | What You'll Learn |
|---|---|
| What Is x402? | The open protocol for machine-native HTTP 402 payments |
| What Is HTTP 402? | The history and revival of the "Payment Required" status code |
| Crypto Payments for APIs | Why stablecoin micropayments are replacing API keys for autonomous agents |
Reference
| Guide | What You'll Learn |
|---|---|
| Glossary | Definitions for A2P, P2P, 10DLC, TCR, CPaaS, CAIP-2, EIP-3009, and 50+ more terms |
MCP (Model Context Protocol)
Use Dial x402 as an MCP server for any AI agent framework.
How SMS Works: PSTN, SS7, and Message Routing Explained
A technical guide to how SMS messages travel through the PSTN, SS7 signaling, SMSC routing, SMPP protocol, and how virtual numbers connect to carrier networks.