The NR500-P4G router has dual SIM card slots, 4 LAN ports or 1 WAN & 3 LAN ports, RS232 and RS485 interfaces are provided to support Serial to IP communication and 2 DI & 2 DO. There is also a version that has WiFi, NR500-P4GW.In addition to the Router function, with the help of Apps, you can access a library of functions that NavigateWorx has developed. It is also possible to get customized Apps. Some examples are: Modbus Master, Modbus Slave, VRRP, SMS Messages, IPsec VPN, PPTP VPN, L2TP VPN, AT over IP and Dynamic Routing.