If your dongle is not in the officially supported 3G/LTE list, but manufactured by the following vendors, there is a good chance it will work

• Huawei
• ZTE

Some USB dongles may be branded independently using the telecommunication provider's name such as Vodafone, T-mobile, O2, etc. A closer examination at the sticker label can usually reveal the original equipment manufacturer. 

If you do not have one of the dongles listed above and do not intent to buy any at the moment, you will be delighted to know you can also connect any Android® or Apple® based smartphone with a valid data subscription to the USB port, which alternatively functions like a 3G/LTE dongle.

In a recent public survey, most adult owns at least 2 or more smartphones, thanks to the brilliant ideas of telecommunication providers with their bundled phone subscription to keep you tied to their services. These subscriptions are renewed every year or once every 2 years, offering you a free phone, which you simply find it very difficult to resist. Look around, chances are that you may find a spare phone lying somewhere around in the house from your previous contract subscription.

Android® is a trademark of Google Inc.
Apple® is a trademark of Apple Inc., registered in the U.S. and other countries.
Huawei is a registered trademark of Huawei Technologies Co., Ltd registered in China and other countries.
ZTE is a registered trademark of ZTE Corporation

If you are using some of the newer ip cameras from which support UID feature, there is entirely no need for port forwarding, DDNS, etc. These are plug and play ip cameras which usually feature a QR code, which you add the ip camera by scanning the QRcode from the supplied app. You can connect 2 or more of such ip cameras wirelessly to the V4 and if the V4 is properly connected to the internet via the WAN port, Wireless extending or 3G/4G dongle, you should easily access the ip cameras from another remote connections from the supplied app, without having to know any IP address, DDNS or port.

If your ip camera does not support the UID feature, it will be very challenging as most 3G/4G connections are assigned a private address range. The common gateway IP address is shared by many other 3G/4G users.