DTAC is send adverts as class-0 text message. 

Class-0 text messages are reserved for warnings in case of emergency, earthquake, tsunami a. s. o. 

 

 

On 6/29/2020 at 10:28 AM, CH1961 said:

Class-0 text messages are reserved for warnings in case of emergency, earthquake, tsunami a. s. o.

Class-0 just directs the "Flash SMS" to appear direct to screen. It's not a 'reserved' type. 

 

And, yes, it's annoying when providers or phone manufactures use channels meant to send priority or sensitive messages are used to serve ads.

 

 

See Messente SMS api website for a more full description of Flash SMS and it's purpose. 

 

"Flash SMS is actually a classification of SMS with there being 4 in total. While the regular SMS message is classified as a ‘Class 1’ message, flash SMS messages are classified as ‘Class 0’ messages, which classifies them as most important SMS messages. That is why they get displayed on the main screen without any user interaction needed. However, it’s important to note that users will only be able to see the last message they receive if multiple flash messages are sent. 

 

"This feature is most often used for sending one-time, or primary, PIN-codes and passwords, credit card information, legal matters related information, as well as emergency messages that need to be seen right away. 

 

"Since the message is not stored on the phone, there’s no concern of limited storage space, or that the information could be stolen along with the phone. The option to save the SMS still exists, but it is not done by default.