3G usb adapter TPLink MA180 on v378.56_2 not working

I am trying to get the 3G usb adapter TPLink MA180 work on Asuswrt-Merlin but not having any success. The service provider just requires an APN name (no authentication) and that is what I have entered in the "USB Modem / USB Tethering" page. But I think it is not even dialing as I dont see any pppd entries in the syslog. From the log, it shows that the adapter is being detected:


3G usb adapter TPLink MA180 on v378.56_2 not working