Using AT command to control GPRS +CMGS under PDU and text to send and receive short messages, what does +z after data content mean?

& ltz is a key combination. Ctrl+z is the terminator 0x 1A used to send data (it must be sent in hexadecimal instead of characters), just as /r is the terminator of an instruction.

When you enter data to be sent in >, you must add an end symbol after it and send it to the past module, then you can judge that the input is over and return to the command state. If you don't send a terminator, even if you add a carriage return, if you send data, you will still be in the > state. This terminator is a small arrow to the right. The ASCII code is 0x1a. Can't find it on the keyboard. Only press ctrl+z (not supported by some serial port software) or 16 to send 0x1a..