SRX100H and AirCard 320U

Hey Experts,

I have a remote box with an AirCard 320U, but the dial in is not working. If I put the SIM card to an AirCard 312U, it is working. I checked on my Linux laptop that the 320U is working. The reason why I prefer the 320U over the 312U is 4G.

The two LEDs of the 320U flash for a second during boot, but remain inactive, both.

root@remote> show modem wireless interface cl-0/0/8   
Wireless modem firmware details 
  Modem firmware version: SWI9200X_03.05.23.09ap r5836 carmd-en-10527 2013/06/17 18:01:23
  Modem Firmware build date: 06/17/13
  Card type: AirCard 320U
  Modem manufacturer: Sierra Wireless, Inc
  Hardware version: 1.0
  Current modem temperature: 23 deg C
  Factory serial number (FSN): CC42353002110102
  International mobile equipment identity
            (IMEI): 357272045242728
  Modem PIN security status: Enabled
  SIM status: SIM Okay
  SIM lock: Unlocked
  SIM user operation needed: No Op
  Retries remaining: 0
Wireless Modem Network Info 
  Current Modem Status: Low Power Mode
  Current Service Status: No Service Available
  Current Service Type: Invalid Service
  Current Service Mode: None
  Current Band: 0
  Roaming Status: No
  Network Selection Mode: Automatic
  Network: 0
  Mobile Country Code (MCC): 0
  Mobile Network Code (MNC): 0
  Location Area Code (LAC): 0
  Routing Area Code (RAC): 255
  Cell Identification: -1
  Scrambling Code: 0
Radio statistics
  Current radio signal strength: -110 dB

Here are the configs for the modem interface:

root@remote> show configuration | display set | match cl-0/0/8    
set interfaces cl-0/0/8 modem-options init-command-string AT+CGDCONT=1,IP,apn.carrier.tld
set interfaces cl-0/0/8 dialer-options pool 1 priority 100
set interfaces cl-0/0/8 cellular-options gsm-options select-profile profile-id 1
set interfaces cl-0/0/8 cellular-options gsm-options radio-access automatic
set interfaces cl-0/0/8 cellular-options gsm-options encrypted-sim-unlock-code "$9$NqdYgZUjfQFGU"

The profile-id 1 remains inactive:

root@remote> show modem wireless interface cl-0/0/8 profiles 
Profile details
  Max profiles: 16
  Default profile Id: 16

Profile 1: Inactive
  Valid: TRUE
  Username: user
  Password: pass
  Access point name (APN): apn.carrier.tld
  Authentication: PAP

Is the firmware of the AirCard the right one? Or why is the card in the low power mode? I assume the card is not probably initialized, but I have no clue, how...