SMS Glossary

SMS glossary: messaging terms explained

30 plain-English definitions of the terms that come up when Australian businesses send text messages — encoding, segments, sender IDs, delivery receipts, APIs and compliance. Each entry explains what the term means and how it affects what you pay and what gets delivered.

A

A2P messagingA2P (application-to-person) messaging is any SMS sent from software to a mobile handset — order confirmations, appointment reminders, one-time passcodes and marketing campaigns — as opposed to P2P messages typed by one person to another.Read definition Abandoned cart SMSAn abandoned cart SMS is an automated text sent to a shopper who added items to an online cart and left without checking out, prompting them to complete the purchase.Read definition ACMAThe ACMA is Australia's communications regulator. It enforces the Spam Act 2003, administers the SMS Sender ID Register, and sets the industry codes that carriers and messaging providers operate under.Read definition Alphanumeric sender IDAn alphanumeric sender ID is a text name — up to 11 characters — that appears in place of a phone number when a business sends an SMS, so the message shows as coming from a brand rather than a number.Read definition

B

Bulk SMSBulk SMS is sending one message to many recipients at once from a single platform, typically with personalisation fields, scheduling and per-recipient delivery reporting.Read definition

C

Click-through trackingClick-through tracking replaces a link in an SMS with a short tracked URL, so the sender can see how many recipients opened it and which campaign drove the traffic.Read definition

D

Dedicated numberA dedicated number is a mobile number reserved for one business, used both to send SMS and to receive replies in a shared inbox.Read definition Delivery receiptA delivery receipt (DLR) is the status update a mobile network returns after an SMS is processed, confirming whether the message reached the handset, is still pending, or failed.Read definition DLRDLR is the industry abbreviation for a delivery receipt — the carrier's status callback telling the sender whether an SMS was delivered, failed or is still in flight.Read definition

E

E.164E.164 is the international telephone numbering standard. A number in E.164 format starts with a plus sign and the country code, contains digits only, and is at most 15 digits long — for example +61412345678.Read definition

G

GSM-7 vs UnicodeGSM-7 and Unicode (UCS-2) are the two character encodings used for SMS. GSM-7 fits 160 characters in a single message part; Unicode is required for emoji and non-Latin characters and cuts a single part to 70 characters.Read definition

K

Keyword automationA keyword automation is a rule that runs when someone texts a specific word to your number — sending an auto-reply, saving the contact, adding them to a group, or opting them in or out.Read definition

M

MCP serverAn MCP server exposes tools to an AI agent through the Model Context Protocol, so assistants like Claude, ChatGPT, Cursor, Windsurf, Gemini and Lovable can perform real actions — such as sending an SMS — rather than only generating text.Read definition Message concatenationMessage concatenation is the mechanism that splits a long SMS into multiple parts and rejoins them on the recipient's handset so it appears as one message.Read definition MO and MT messagesMT (Mobile Terminated) messages are sent from an application to a handset. MO (Mobile Originated) messages travel the other way — a person texts your number and the message arrives in your platform.Read definition

O

Opt-inAn opt-in is a recipient's consent to receive marketing messages. Australian law recognises express consent, given directly, and inferred consent, arising from an existing business relationship.Read definition Opt-outAn opt-out is a recipient's request to stop receiving marketing messages. Under Australian law it must be honoured within five working days, and in practice good platforms process it instantly.Read definition

S

Sender ID registrationSender ID registration is the process of recording a business's alphanumeric sender name on Australia's SMS Sender ID Register so carriers can block anyone else from sending under that name.Read definition Short codeA short code is a shortened phone number, usually four to six digits, leased by a business for high-volume SMS. Short codes support high throughput and are widely used for keyword campaigns and two-way messaging.Read definition SMPPSMPP is the binary protocol used between SMS gateways and mobile network operators to exchange messages at high volume over a persistent TCP connection.Read definition SMS 2FASMS 2FA is two-factor authentication delivered by text message: after entering a password, the user receives a one-time code by SMS and enters it to complete sign-in.Read definition SMS APIAn SMS API is an HTTP interface that lets software send and receive text messages programmatically, usually with a single authenticated POST request carrying the recipient, the sender and the message body.Read definition SMS creditAn SMS credit is the prepaid unit an SMS platform charges per message part. With Texto, one credit is 3¢: an Australian message part costs one credit, and a New Zealand message part costs three.Read definition SMS gatewayAn SMS gateway is a service that connects software to mobile networks so applications can send and receive text messages without a physical phone or SIM card.Read definition SMS segmentAn SMS segment is one billable part of a text message. Messages longer than a single segment are split, sent as separate parts, and reassembled on the handset — but each part is charged.Read definition Spam Act 2003The Spam Act 2003 is the Australian law governing commercial electronic messages. It requires consent before sending, accurate sender identification, and a functional unsubscribe facility in every marketing message.Read definition

T

ThroughputThroughput is the rate at which an SMS route can deliver messages, measured in messages per second. It determines how long a bulk campaign takes to land, not whether it will.Read definition Transactional vs marketing SMSTransactional SMS delivers information a recipient is expecting — an order confirmation, appointment reminder or verification code. Marketing SMS promotes a product or offer, and carries consent and unsubscribe obligations.Read definition Two-way SMSTwo-way SMS is text messaging where the recipient can reply and the reply arrives back in the sender's platform, turning a broadcast into a conversation.Read definition

V

Virtual mobile numberA virtual mobile number is a standard mobile number that lives in software instead of on a SIM card, letting a business send and receive SMS through a platform rather than a handset.Read definition

Keep exploring

SMS pricing3¢ per SMS to Australia, no contracts or monthly minimums.Read more SMS APIOne REST endpoint, API key auth, signed delivery webhooks.Read more Free SMS toolsNumber formatter and character counter, free in your browser.Read more SMS marketing guideConsent, compliance and campaign planning for Australia.Read more

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