Alphanumeric Sender ID
Sender ID is case sensitive. Allowed letters: a–z, A–Z, digits 0–9, space, and any combination of uppercase and lowercase.
Allowed special characters: +
The following are not allowed: consecutive spaces, spaces at the beginning or at the end, accents (tildes), series of the following symbols: #, %, (), ,, /, :, ;, <, >, =, ¡, !, ¿, ?, [], € (similar currency symbols included), and numerics.
Abbreviations will be accepted for public administrations.
For companies, they will be accepted provided they comply with the linking rule set out in Article 3 of the circular.
Aliases with a generic name that does not allow the sender to be identified or creates confusion with the names of official bodies or companies (for example, "message," "Bank," "Flight," "Urgent") will not be permitted.
Aliases that correspond to proper names (people or places) should not be used, unless they are associated with the owner (for example, "AytoMadrid" would be acceptable, but not "Madrid") or coincide with a registered trademark or trade name of the owner (e.g., "Santander").
Aliases may not contain offensive, discriminatory, hateful, or public order-related expressions.