When a message is in transit (not yet received by the intended recipient's device), some wireless carriers will keep the message(s) available for some period of time until the recipient's device can receive it. The amount of time the message will be available for the recipient's device to receive it depends largely on what the wireless carrier chooses, although some wireless carriers will hold a message for up to 48 hours for reception by the recipient's device, and then it is discarded.
Generally, they are not secure. Anyone with the necessary skills and equipment can easily intercept SMS/MMS messages. Some cellular carrier’s networks are more secure than others.
The general answer is NO, not unless there is not another way to communicate and loss of life or property is imminent. Please note that if you make use of SMS/MMS for a mission, then you also need to export those messages into a file, along with the name(s) and phone number(s) of the senders and recipients. Then upload this file to the "Mission Files" section of the mission in WMIRS. The uploaded file should not require the purchase of software to be able to view/read the uploaded file.
MMS stands for Multi Media Messaging Service.
SMS stands for Short Message Service (also called Text Service).
Your cellular carrier generally holds messages until your device reconnects to the cellular network. Each cellular carrier has different message retention times. Once that amount of time has passed, messages that have been in your cellular provider's network are discarded with no notification to the sender or the recipient.
There a several reasons that might prevent a device from sending messages. Some of the more common reasons are:
There a several reasons that would prevent a device from receiving messages. Some of the more common ones are: