What the letters mean
A2P is application-to-person: a business sending texts through software, rather than one person texting another from their own phone. 10DLC is a 10-digit long code, which is a normal local phone number. Put together, A2P 10DLC means business texting from a local number, and in the US it has to be registered.
Who’s involved
| Who | What they do |
|---|---|
| The brand | Your business, the company sending the texts. It’s registered with its legal name and address and, unless it’s a sole proprietor, its EIN. |
| The campaign | What you’ll send and why, such as replies to customers, appointment reminders or marketing. |
| The messaging provider (CSP) | The company whose platform sends your texts. It registers your brand and campaign for you. |
| The Campaign Registry (TCR) | The registry where brands and campaigns are recorded, so everyone in the chain knows who is sending what. |
| Carriers | Deliver the texts, and approve some sensitive campaign types themselves. |
Two details from TCR’s own resources are worth knowing. Businesses can’t register directly with TCR: you go through a messaging provider, which handles it for you. And TCR itself doesn’t review or approve campaigns. The provider and its upstream partners do, so approval times vary from provider to provider.
Why it exists
Carriers want to know who is sending business texts, to cut spam and scams. TCR describes 10DLC as a channel where brands and providers are verified before they’re allowed to send, and where both the “who” and the “what” of each campaign are known upfront. Unregistered business texts from local numbers can be filtered or blocked; registered ones are delivered more reliably.
Three kinds of business texts
The wireless industry group CTIA sorts business texts into three types, each needing a different level of permission:
| Type | Example | Permission expected |
|---|---|---|
| Conversational | A customer texts you first and you reply about their request | None beyond the customer starting the conversation |
| Informational | Appointment reminders, booking confirmations, alerts | The customer gave you their number and agreed to texts for that purpose |
| Promotional | Coupons, sales, marketing | The customer’s written agreement first |
CTIA notes that adding a call to action, such as a coupon code, to an informational text may turn it into a promotional one. That’s why reminders and missed-call texts should stick to the job.
Opt-outs: STOP means stop
CTIA’s guidance says standard “STOP” wording should be used for opt-out instructions, but plain-language requests such as stop, end, unsubscribe, cancel, quit or “please opt me out” should also be honored. Capitalization and punctuation don’t change that. After someone opts out, they get one final confirmation and nothing more.
What you need to do with 2Line.AI
Nothing extra. 2Line.AI’s brand and campaign are already registered, and each new number is added to that campaign when you pick it. The app says “registering” until carriers finish, then texting is live. Program messages honor STOP and HELP.
If you use another provider
- Have your legal business name, address and EIN ready, exactly as they appear on your IRS paperwork. Sole proprietors without an EIN register as sole proprietors.
- Describe your campaign clearly: what you’ll send, to whom and why. TCR notes that a vague description can get a campaign rejected.
- Explain how customers agree to texts, such as a checkbox on your booking form or texting you first.
- Prepare sample messages that include your business name and how to opt out.
- Wait for approval before sending. If a campaign is rejected, your provider gets the reason and can help you fix and resubmit it.
Good texting habits
- Text people who contacted you or agreed to texts.
- Put your business name in the first message.
- Honor STOP and plain-language opt-outs right away.
- Keep messages about their job or booking, and save promotions for people who agreed in writing.
- Don’t add people to a marketing list just because they called you.
Sources (checked October 2026): The Campaign Registry: home; The Campaign Registry: resources and FAQ; CTIA: Messaging Principles and Best Practices (May 2023).