Missed Call and Business Texting Glossary

Texting rules and registration

A2P messaging

Application-to-person messaging: texts that software sends on behalf of a business, such as appointment reminders and automatic replies like missed call text back. The opposite is person-to-person texting between individuals. US carriers treat business texting as A2P and expect it to be registered. More: A2P registration guide

A2P 10DLC

The US carrier system for business texts sent from ordinary 10-digit local numbers (10DLC means “10-digit long code”). The business registers a brand (who is sending) and a campaign (what it sends and how people opt in). Carriers block or filter unregistered traffic. Registration carries one-time and monthly fees: in October 2026 HighLevel listed $22.50 one-time plus $1.50 to $10.50 a month for a low-volume campaign, and Quo and Grasshopper listed $19.50 one-time plus a monthly fee. More: A2P 10DLC checker · A2P registration guide

The Campaign Registry (TCR)

The third-party registry the major US carriers use to collect A2P 10DLC brand and campaign registrations. Your texting provider submits to TCR for you and passes on its fees.

Brand and campaign (A2P)

The two parts of an A2P 10DLC registration. The brand is the business: legal name, tax ID (EIN), address and contact. The campaign describes the messages: use case, sample texts, how people opt in, and opt-out and help wording. Carriers review it, and HighLevel says campaigns are often rejected when these details don’t match the business records, website or real opt-in flow. More: Check your campaign

Sole Proprietor brand

A lighter A2P 10DLC registration for a one-person business without an EIN. It has tighter limits than a standard brand; in HighLevel it can be linked to only one phone number. More: A2P registration guide

Toll-free verification

Toll-free numbers (800, 888, 877 and so on) don’t use 10DLC registration. Before texting at scale from one, the business completes a separate toll-free verification with its provider.

CTIA Messaging Principles

Best-practice guidelines from CTIA, the US wireless industry association, for business texting: get consent, honor STOP and HELP, identify the sender, and keep content within the stated use. Carriers and registration reviewers apply them, so they matter even though they are not a law.

TCPA

The Telephone Consumer Protection Act, the 1991 federal law behind the FCC’s rules on autodialed and prerecorded calls and texts (47 CFR 64.1200): consent, calling-time limits, do-not-call lists and opt-out handling. Some states add their own “mini-TCPA” laws. More: Laws by state

Prior express written consent

The strongest form of consent under the FCC’s TCPA rules: a signed (including electronic) agreement that names the number and authorizes marketing calls or texts using an autodialer or prerecorded voice. A one-time reply to someone who just called you is a different situation from ongoing marketing, which is where written consent matters most. More: Laws by state

Quiet hours

Times when marketing calls and texts shouldn’t go out. Federal rules bar telephone solicitations before 8 a.m. or after 9 p.m. in the recipient’s local time (47 CFR 64.1200(c)(1)), and some states set narrower windows. Some states carve out replies to a customer’s own inquiry and others don’t, so check your state. More: State-by-state table

Mini-TCPA laws

State laws modeled on the federal TCPA, often with stricter consent, quiet-hour or autodialer rules. Florida’s Telephone Solicitation Act is one example. More: Laws by state

Opt-out keywords (STOP)

Replies that mean “stop texting me.” Under the FCC’s rules, words such as STOP, QUIT, END, REVOKE, OPT OUT, CANCEL and UNSUBSCRIBE count as an opt-out, and the request must be honored within 10 business days (47 CFR 64.1200(a)(10)). Most texting platforms block further messages automatically. More: Laws by state

Short code

A 5- or 6-digit number used for high-volume texting such as national promotions. Short codes are leased and approved separately and are rarely needed for missed call text back.

Message length and format

SMS segment

The unit carriers bill and deliver texts in. A message in the standard GSM-7 alphabet fits in one segment up to 160 characters; longer messages are split into 153-character segments. If a single character forces UCS-2, the limits drop to 70 and 67. Platforms like HighLevel charge per segment, so a 161-character text costs twice as much as a 160-character one. More: Text generator with a segment check

GSM-7

The basic 7-bit character set for SMS. It covers English letters, digits, common punctuation and some accented letters (for example é, ñ and ü), but not á, í, ó or ú, emoji, or curly quotes. More: Spanish templates

UCS-2 (Unicode SMS)

The encoding a phone or platform switches to when a message contains any character outside GSM-7, such as an emoji, a curly apostrophe or á. It cuts a single segment to 70 characters (67 per segment when split), which can triple the cost of a text.

MMS

Multimedia messaging: texts with an image, video or file. MMS is priced separately from SMS and isn’t needed for a text-back.

Phones and call handling

Missed call text back

An automation that texts a caller when their call isn’t answered, so they can reply in writing instead of trying another business. Tools differ on who gets the text (every caller, first-time callers, or existing customers) and how often. More: Templates and setup · App comparison

Conditional call forwarding

A carrier setting that forwards calls only when your line is busy, unanswered or unreachable. It lets a texting or answering service catch missed calls without moving (porting) your main number.

Number porting

Moving an existing phone number from one provider to another. Keep the old service active until the port completes so calls and texts aren’t lost in between.

Call tracking number

An extra number that forwards to your main line and records which ad, listing or campaign a call came from. Several field-service apps sell it as a phone add-on.

IVR (phone menu)

Interactive voice response: the “press 1 for service, 2 for billing” menu. A menu can route emergencies to on-call staff, but callers who hang up in the menu may count as missed calls.

CNAM (caller name)

The caller-ID name shown on the other person’s phone. Registering your business name helps customers recognize your callback.

STIR/SHAKEN

The caller ID authentication framework US carriers use to verify that a call really comes from the number shown. It helps reduce spoofed robocalls and “spam likely” labels on legitimate callbacks.

AI and answering

AI receptionist

Software that answers phone calls with a synthetic voice, follows a script or prompt, collects details, and can book appointments or transfer calls. It needs clear rules for emergencies and for what it must never promise. More: Setup for HVAC and plumbing · AI vs answering service

Answering service

Live people who answer your calls with your script, usually priced per minute or per call. Some now mix in AI. More: Answering service cost · Smith.ai alternatives

After-hours answering script

The written greeting, safety lines, triage rules and intake fields that whoever answers at night (a person or an AI) must follow. More: Plumbing · HVAC · Electrical

HIPAA and BAA

HIPAA is the US health privacy law that applies to dental and medical practices. A business associate agreement (BAA) is the contract a practice signs with a vendor that handles patient information. Check whether a texting or AI vendor will sign one before using it with patients. More: Dental text-back and HIPAA · Dental AI receptionist

HighLevel terms

LC Phone (HighLevel phone system)

HighLevel’s built-in phone and SMS service. Numbers, calls and texts are billed by usage from the account’s wallet (in October 2026: $1.15 a month per local number and $0.00747 per SMS segment, plus carrier fees). More: HighLevel pricing

Wallet (HighLevel)

The prepaid balance that HighLevel draws usage charges from, such as phone, SMS, email and AI. Agencies can recharge usage to clients through rebilling. More: HighLevel pricing

Sub-account (HighLevel)

One business’s workspace inside a HighLevel agency account, with its own contacts, phone numbers, calendars and automations. The Starter plan includes 3 sub-accounts; Unlimited removes the cap. More: Plan comparison

Workflow (HighLevel)

HighLevel’s automation builder: a trigger (for example, a missed call) followed by actions (send a text, wait, notify staff). HighLevel suggests a workflow with a wait step when you want more control than the built-in missed call text back. More: Text-back setup

DND (Do Not Disturb)

A HighLevel contact setting that blocks messages to that contact on one or all channels. HighLevel says its missed call text back respects each contact’s DND settings.

Voice AI (HighLevel)

HighLevel’s AI phone agent for inbound calls, billed by the minute on top of phone charges. More: Voice AI review and pricing

Conversation AI (HighLevel)

HighLevel’s AI bot for text channels such as SMS and web chat. It can answer questions and, when connected to a calendar, book appointments from a text conversation. More: AI Employee plans

AI Employee (HighLevel)

HighLevel’s bundle of AI features (including Voice AI and Conversation AI), sold per sub-account on a usage plan or a flat unlimited plan. More: Usage vs unlimited

SaaS mode (HighLevel)

A feature of HighLevel’s top plan that lets an agency resell HighLevel under its own brand with its own subscription prices and usage markup. More: SaaS mode guide

Rebilling (HighLevel)

Charging a client sub-account for its phone, email and AI usage. On the Unlimited plan phone and email are rebilled at cost; the Agency Pro plan lets the agency add its own markup. More: SaaS mode guide

Snapshot (HighLevel)

A saved copy of a sub-account’s setup (funnels, workflows, calendars and similar assets) that can be loaded into another sub-account. Agencies use snapshots to repeat a setup for many clients. More: Selling text-back as an agency

Where to go next

Use the missed call text generator to write a one-segment text, run the A2P 10DLC checker before you register, or pick your trade on the trade hubs page.