Kalo saya pake TP-Link MR320, nggak perlu ribet setting, hrg 300rb an, koneksi utama pake speedy begitu speedy putus, bbrp detik kemudian otomatis nyambung ke koneksi cadangan bisa modem CDMA/ GSM yg udah ditancepin sebelumnya di interface si router.
Sayangnya, saat speedy udah normal, koneksi nggak auto connect ke speedy seara otomatis... 
TL-MR3220
Internet Access Help
You can select the Internet Access on this page. The Device is designed to work with either WAN port or 3G/4G USB modem, and supports automatically take over back up with 3G/4G access as Ethernet WAN failover.
3G/4G Only
In this mode, the Device will try 3G/4G access only. WAN access is disabled.
3G/4G Preferred
In this mode, the Device will try 3G/4G access first;
When 3G/4G access fails and WAN access is valid, or when no 3G/4G USB modem is inserted, the Device would switch to WAN access;
When the Device succeeds to connect to the 3G/4G network, the Device would stop the WAN connection and switch back to 3G/4G access immediately.
WAN Preferred
In this mode, the Device will try WAN access first;
When the WAN access fails, and 3G/4G access is valid, the Device would switch to 3G/4G access;
When the Device succeeds to connect to the WAN network, the Device would stop the 3G/4G connection and switch back to WAN access immediately.
WAN Only
In this mode, the Device will try WAN access only. 3G/4G access is disabled.
Note:
- If you are using the 3G/4G Preferred or WAN Preferred, the Device would connect, disconnect or switch the current access automatically. The Connect/Disconnect button(on 3G/4G, PPPoE, PPTP, L2TP) and some related parameters could not be set manually.
- Only when the WAN connection is Dynamic IP, Static IP or PPPoE can the Device support the switch between 3G/4G mode and WAN mode.
Click the Save button to save your settings.
