need AT-Command to copy files from sd-card

i have usb-modem that i can comunicate with it using AT-Command. i can send and recive sms using it. we know that we can insert an SD-Card into the usb-modem and use it as a storage device but i been stuck for days searching how i can work 开发者_运维知识库on files on sd card using AT-Command?? please help. thanks in advance

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I don't think you can do this. The AT command-set is only for doing "phonestuff". Calling, texting (which in itself is an extension), and such.

The usual reason for usb-modems to have built-in storage is so you can store the drivers there. This would let you use the modem on any computer without needing to connect to the internet to get the drivers.

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Are you sure the modem doesn't expose the card as a drive as other USB devices do (e.g cameras, phones, etceteras)? I can't see a way of retrieving files off it using ATxx commands.

Edit, I did a little digging and found this:

https://wiki.archlinux.org/index.php/Huawei_E1550_3G_modem#AT_commands

And I am wondering if any of the following can point you in the right direction:

AT^U2DIAG=0 - the device is only Modem
AT^U2DIAG=1 - device is in modem mode + CD ROM
AT^U2DIAG=255 - the device in modem mode + CD ROM + Card Reader
AT^U2DIAG=256 - the device in modem mode + Card Reader
AT+CPIN=<PIN-CODE> - enter PIN-code
AT+CUSD=1,<PDU-encoded-USSD-code>,15 - USSD request, result can be found (probably) in /dev/ttyUSB2.

So it would appear you can put the device in a card-reader mode using AT^U2DIAG=256. I'd be interested to see if, when you execute this, whether your drive will then be mapped. I can't really find anything to get files off it after you do this.