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System Requirements

Getting Started

Before getting started with Aerialink, your system must be capable of supporting the following elements for the program types appropriate to you. To ensure that you have identified your program type correctly, please review the definitions below:

One-Time Program: Also referred to as a “query” service; a program in which the end-user texts a keyword to receive the desired response a single time, and will receive no additional contact from that service unless they text in to engage the service again.
Recurring Program: Also known as a “subscription-based” service, end-users who opt into recurring programs will receive messages at regular or event-triggered intervals over a given period of time without additional end-user interaction or prompting required.
Multi-Program Short Code: If your business has more than one program running on the same short code—whether they are of similar or differing type—it must support a multi-program HELP menu.

The following is a series of brief articles describing what your system will need to support in order to run a compliant short-code program. For more information about program compliance, please check out the related pages links, or free-browse our Compliance section.


There are two clear types of keywords at work in your mobile program. Required Keywords, such as HELP and STOP, are required by law to function in one specific way. Program keywords can be used to create message responses unique to your program. Here are some rules to keep in mind about how program keywords function:

Campaign Keywords

Campaign keywords are chosen by the content provider to trigger desired responses such as opting an end-user in or prompting a portion of the service. Here are some things to keep in mind about Campaign Keywords:

  • Must be be between three and fifty characters long
  • Must consist of letters, numbers and spaces* only
  • Must begin with a letter
  • Cannot be case-sensitive (Join, JOIN and join elicit the same response)
  • Cannot be duplicated on the same short code
  • Cannot be required keywords such as HELP and STOP

*Spaces in keywords are acceptable only for customers using Aerialink Messenger to handle their keywords.

Required Keywords

  • HELP
  • AIDE*
  • INFO*
  • STOP
  • ARRET*
  • END
  • QUIT

* Required for Canadian campaigns only.


“HELP” must be advertised as the keyword-driven means to obtain more information and must be supported on all mobile programs.

  • HELP should return a response regardless of whether the end-user is presently or was ever opted into the program.
  • HELP must work in the native language of the program.
  • Non-English programs must not return an error message to the English keyword.
  • AIDE is the French version of HELP and is required as an accepted support keyword for all programs running in Canada.


“STOP” is the keyword required in all advertising and messaging, but its synonymous keywords–END, QUIT, CANCEL, UNSUBSCRIBE and ARRET*–must also be live, functional, return the same response as “STOP” and successfully opt the end-user out of the mobile program.

Some other things to consider about the STOP keyword are:

  • STOP and HELP should return a response to all users - even those who never opted into the program.
  • STOP must work in the native language of the program.
  • Non-English programs must not return an error message to the English keyword.
  • ARRET is the French version of STOP and is required as an accepted opt-out keyword for all programs running in Canada.
  • Short code programs must ignore subsequent non-keyword text included in STOP requests. (e.g., an MO containing the words “please stop” should see the “stop” and complete the STOP process regardless of the presence of the non-keyword text.)
  • The opt-out process cannot contain a menu. End-users who are opted into multiple programs at the time they send STOP should receive either a single, blanket opt-out confirmation for the entire code or individual, program-specific confirmations for each of the programs into which they were opted.*

*Please note that the use of STOP ALL as a multi-opt keyword is no longer accepted. The use of “Powered by [Sponsor Name]” is also no longer a recommended solution to multi-program responses, as all codes should support the capability of checking subscriber lists to return responses specific to the end-user’s subscriptions.

The following keywords are “reserved.” While they are not technically required keywords such as “stop,” they are disallowed from use by Aerialink customers in the following applicable groups.

  • LINK

The LINK keyword is reserved across all Aerialink codes both shared and dedicated for Aerialink system use

Shared Short Codes

Bear in mind that the keywords listed below are reserved in addition to “LINK” and any required keywords for users of shared short codes.

  • JOIN
  • YES


Subscription Database

The FCC TCPA of 2013 requires that a mobile end-user give “prior written express consent” before being opted into a mobile service to receive marketing messages. This message transaction creates a time-stamped proof of opt-in, leaving no space for dispute that the customer asked to receive the content being sent to them. According to the same act, every program must allow the customer to opt-out if desired. If a customer opts-out, that transaction is also recorded with a time stamp as proof of opt-out. This simple process is a clean, trusted system for maintaining a compliant subscription database. Your system must maintain this database.

Double Opt-in

An optional double opt-in requires users who opt into a mobile program via a non-SMS-initiated method to verify their mobile number by responding to a confirmation request SMS with “YES” or a PIN number in order to confirm their subscription. While double opt-ins are no longer required they are recommended as a campaign best-practice for any mobile program with non-SMS-initiated opt-ins.

One-Time “Opt-Ins”

One-time programs are not required to formally “opt in” users or maintain a subscription database. However, one-time programs also cannot use the contacts collected in this manner for marketing purposes.


A subscriber must be able to cease participation with any program at any time. The Aerialink Platform will block any attempted messages sent to destination end-users who have previously texted Aerialink customer short codes or long codes with the following carrier required keywords:

  • STOP
  • ARRET*
  • END
  • QUIT

Long Code “Blocking”

End users who send one of the above keywords to an Aerialink long-code will receive the following message confirming their Block Request: You have successfully blocked [###########] and will no longer receive messages from this number.

An administrator of the Aerialink platform can release a long-code block for an end-user within the Platform User Management Portal.**

*“ARRET” is the French version of “STOP” and is required as an accepted opt-out keyword for all programs running in Canada.

**Customers may be eligible for exemption from this block feature based on their approved messaging use-case

Message Flow

The most important thing to note when creating or revising your message flow is that in order for it to pass certification, the live messages which your system pushes out must identically match the messages detailed in your short code application form (or “Program Summary”). Therefore, you must ensure that your messaging application supports the logic required for compliant message flow, so that when carriers test your mobile program with live devices, they will receive the expected results documented in your program summary. Please read on for details about the functions your system must support for compliant message flow:

Monthly Subscription Reminder

A user who is subscribed to a Recurring Program must receive monthly reminders of their subscription. A compliant example is outlined below.

Subscription Reminder Outbound

Sponsor & Program Name: Subscribed to keyword! product description. Msg&data rates may apply. URL or Toll-free# Reply HELP for help, STOP to cancel.

URL Encoding

Standard URL Encoding practices should be used in constructing the URL call to Aerialink which will insure any non-ASCII characters are URL-encoded with their proper replacement value.

Data Coding Scheme

We recommend that you leave your DCS value set to 0. In the United States, avoid the use of unicode (UTF) in text messages, as it is not widely or reliably supported by domestic carriers. For more information, please see our articles on Encoding & Character Sets and Data Coding Scheme values.

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