Qnewbie

You might need watchdog for your 3G connection too:
http://forum.mikrotik.com/viewtopic.php?f=9&t=69807

I set the 3G modem as failover internet connection and use dial-on-demand but in your case you might need the watchdog.

角色

Thanks you for your advice.

By the way, what the lowest and best offer of the data plan in your area?

Qnewbie

I have been using mobile phone+surf(speed<1Mb/s) plan(~HK$70) per month for more than one year now.

There was a free data plan(1G/month), which I missed the promotion.

角色

The plan is very good and not expansive. How comes the mobile phone charge is so high?With the low price data plan, you could make and receive voip calls via the data plan, right?

Qnewbie

Yes, I am using its data plan to make calls.

角色

The major issue using data plan to make phone calls is the delay! However it will be much cheaper then ordinary mobile operators.

角色

When the same data card was moved to another 3G modem which is specifically used for China Union network, I was not able to access the broadband internet.