3G/4G & LTE Base HAT, Telit modem kit trouble powering up first time

kit just arrived. followed tutorial. no green power light, only red.
now when I try minicom -D /dev/ttyUSB2 -b 115200 I get “cannot open…Device or resource busy”
I unplugged it all, powered up several times, same
Also in minicom it is unresponsive to AT command

Hi @jilse22,

What was running when the problem occurred? Make sure ttyUSB2 is not busy. Please try sending AT commands via ttyUSB3. Is ppp_connection_manager active?

Please check out our troubleshooting guide and see if there is a possible solution to your problems. Any information you can provide us would be greatly appreciated.