Several Basic concepts of SMS Technology

1. the validity period of the text message (Validity Period) if the mobile phone is offline, a text message will be temporarily stored in the text message service center. you can also set a time period for the text message, that is, how long the text message will be deleted from the text message service center, so that even if the received mobile phone is converted into an online text message, it will not be sent to the receiving mobile phone. this time period is called the validity period. here is an example to illustrate how to use the validity period. for example, if you find a program played on TV very interesting, your friends may want to watch it too. therefore, you sent a text message to tell your friends about the TV program. suppose this program will last for 1 hour. if his phone is available only after the TV program ends, your short message will be useless to your friends. in this case, you may want to send a one-hour text message to your friends. if his phone is unavailable before the validity period ends, the wireless operator will not send text messages to your friends. the mobile phone should have a menu option for users to set the validity period. after setting, the mobile phone will automatically include the validity period in the outgoing message. 2. information Status Report (sent Status Report) Sometimes you may want to know Whether a text message is successfully sent to the receiving mobile phone. to obtain this information, you need to set a flag in the text message to tell the text message service center that you want a status report about the delivery of this text message. the status report will be sent to you as a text message. the mobile phone should have a menu option to set whether the status report feature is enabled. after the status report is turned on, the phone will automatically set the corresponding Identification Position in the text message sent outside. the status report feature is disabled by default on most mobile phones and GSM/grprs modems. 3. A text message is sent to the SMS service center after it leaves the mobile phone. After arriving at the SMS service center, the SMS service center will return a message to the mobile phone to submit a report to inform you of the error or failure (for example, the Short Message format is incorrect and the SMS service center is busy ). if no error or failure occurs, the SMS service center sends a positive report to the mobile phone. otherwise, a negative report will be sent back to the mobile phone. then, the mobile phone can notify the user of the submission failure and the cause of the failure. if the phone does not receive the report after a period of time, you can confirm that the report has been lost. the mobile phone can also resend the text message to the service center. in the new text message, you can set a flag to tell the service center that this information has been sent. if the previous text message has been submitted successfully, the service center will ignore this new text message and send the report back to the mobile phone. this mechanism prevents the recipient from sending the same message multiple times. sometimes the message submission report mechanism is not used, but is implemented at the bottom layer by message submission confirmation. 4. after receiving a text message, the receiving mobile phone will send a message delivery report to the service center to inform the service center of any errors or failures (for example, because: unsupported SMS format, full storage space, etc ). this process is transparent to mobile phone users (that is to say, the program will automatically handle this process without the need to care about or make any settings ). if no error or failure occurs, the receiving mobile phone will send a positive delivery report to the service center. otherwise, a negative delivery report will be sent. if the sender has previously requested a status report, the service center will send a status report to the sender when receiving the delivery report sent by the recipient. if the service center does not receive the delivery report after a period of time, the delivery report is deemed to have been lost. the service center will send a new text message to the recipient. sometimes the message delivery report mechanism is not used, but the message delivery confirmation is used at the bottom layer. original article: basic concepts of SMS technology supplement: the report submission and delivery of information are transparent to users. That is to say, the user does not need to care about it, and the mobile phone will automatically process it. This is required in the agreement, therefore, no option is provided to enable or disable the function. some mobile phones use the delivery report as an option (Use delivery report). This is actually an sent Status report. When it is enabled, it will receive the status report sent by the message, instead of the delivery report mentioned above. some mobile phones are also called SMS receipts, but they all refer to status reports. in addition, it should be noted that some carriers need to activate their services at an additional charge for sending status reports (or SMS receipts.