How use AT commands in Putty GL inet 750

tell me please, how can i insert AT commands in Putty, for example AT+GSN . when i tried through Putty : -ash: AT+GSN: not found . From Admin Panel AT commands working, but i need via Putty.
i want to add imei change script in /etc/init.d/ ( when you switch on router - auto generate new imei) . I know how generate random 15 digital number, i know how change imei, but i have one little trouble - i can’t use AT commands via Putty.

You can follow this guide:

The guide recommends socat but my Spitz doesn’t have that package installed by default and uses glmodem as its modem manager, rather than the standard openwrt Modem Manager. Would adding the socat package conflict with glmodem?

Does glmodem have its own version of socat that is accessible via ssh?

EDIT: After some more googling, found a mention of the gl_modem command:
gl_modem -B 1-1 AT /dev/ttyUSB2 ATI

I’m unclear what -B 1-1 does. The more basic command below also works.

gl_modem AT ATI

That sends the AT command “ATI”, other AT commands can be sent in that place via SSH

socat is a program to get socket output. You can install it.
But you can simply use cat for this purpose.

-D output debug info
-B use which USB bus, e.g. 1-2, 1-1.3 etc.