LTE-552TJ is for Docomo version.
LTE-552UA is for softbank version

LTE FDD (bands 1, 3, 8, 9, 11, 18, 19, 21, 26)
UMTS /DC-HSPA+ (bands 1, 6, 8, 11, 19)
4G (LTE) 50/100 Mbps
3.75G (HSPA+) 11.5/42.0 Mbps
3G (UMTS) 384/384 Mbps
2G (GSM / GPRS / EDGE) 236/236 Mbps
WiFi
802.11b/g/n 2.4GHz，2T2R，up to 300 Mbps.
INTERFACES
• 1 SIM card interface (3V/1.8V)
• Power supply
• External 2 SMA antenna interface for WiFi 2T2R
 External 2 SMA antenna interface for LTE MIMO.
•Power: 6 Volts ~ 34 Volts (Normal 12Volts 1.5 Amps power supply)
•1 USB OTG (connector USB micro B)
•2 0dB SMA connector for 3G(1 3G main, 1 GPS active), or for 4G which has 3 0dB SMA connectors(1 LTE main, 1 LTE diversity, 1 GPS). GPS is optional.
•Ethernet : 2 Port (10/100/1000 MBps)
•1 of 2 Port support PoE 37V-48(57)V 802.3af.
•1 DB9 Connector
Switch able between RS232 and RS485/422
•4 PIN connector for console, Power(3.3Volts), RX, TX, GNG
•4 Digital I/O
 Software configurable I/O. It is isolated from the processor. It will be able to handle 500V between signal and device.  They will have a single ground pin for both ports.  The Output will be an open collector type.  The input will support up to 30VDC
•4 Analogue I/O
 Voltage input supporting 0-10VDC.  Alternatively the input will detect a current input supporting 4-20mA.  There will be one pin for ground and there may be two pins for input: one for voltage input, one for current input.  The input type will be configurable via software.
•RTC Backup CAP (7 Days Cover)
Button:
WPS,System Reset
LED
Power, 2.4GHz wifi status, 4G status, 2 10/100/1000 LAN ports, Link/Act,WPS
Embedded system
• Linux:. Router can be shared by 250 user at the same time.
Supports OpenWRT，DD-WRT Ralink SDK Linux
Protocol: TCP, FTP, PPTP, HTTP,HTTPS, TFTP, DHCP, NAT, IPSec Pass through, ICMP, IGMP, RIPv2, RIP, OSPF, SNMP, RMON, QoS.
Optional: VPN client or gateway, IPSec client.