I meet the same problem. But i found that normally TP-LINK will connect automatically.

I also need to set the Modem to connect "3G only". Using the MA260 but having the same issues.
The moment it switches over to 2G the connection stops working, then I have to manually restart the connection.
The connection manager does not provide this option to lock it to "3G only".

I have found the AT commands

`GPRSONLY' : AT^SYSCFG=13,1,3FFFFFFF,2,4
`3GONLY' : AT^SYSCFG=14,2,3FFFFFFF,2,4
`GPRSPREF' : AT^SYSCFG=2,1,3FFFFFFF,2,4
`3GPREF' : AT^SYSCFG=2,2,3FFFFFFF,2,4

but I cannot seem to communicate with this modem not even via putty with serial
None of the other connection managers I have downloaded recognises the modem

Please help me to send AT^SYSCFG=14,2,3FFFFFFF,2,4 to this modem so I can have a stable connection.