Hi All, we have been using the Sierra Wireless 320U 4G USB modem and a Mikrotik hAP routers for a while now for out of band management on our network, I remember when we first got the modems and plugged them into a routerboard that we had lots of problems getting them working, then there was the mucking about with PPP or LTE etc etc. Anyway we just bought another 20 of them for more of our sites and I faced the same issue again of not being able to get them to work, so when I finally figured out the issue I thought I would share the details here so that it benefited anybody who needed the information. So this device when plugged into a Mikrotik Router USB port will show up as an LTE interface, you shouldn't need to cold boot the device or anything once it's inserted as some people say, the interface should just appear, this is from my experience anyway on 6.35.x version of ROS with a hAP or RB2011 series. If the interface doesn't appear check to make sure you have the "Ignore DirectIP Modem" checkbox NOT ticked under System/Ports/Firmware, you need to have this unticked for it to work. Once you have the interface appearing the only other settings you need to change are to set the APN within the lte1 interface, and add a DHCP client to the Interface to get your IP address from Telstra. If you have organised it when ordering your SIM, telstra.extranet APN will give you a dynamic public IP or telstra.internet APN will give you a dynamic NAT'd private IP, we chose the former so that we could get into the routers remotely, there is no static public IP option in case you were wanting that..... Now, if you have got to this point and are saying that your device is appearing when you plug it in but doesn't get an IP or the lights do funny stuff then read on. These devices have a feature which kicks off the Telstra software installation when you plug it in, unfortunately this feature breaks the process when you plug it into a Mikrotik routerboard, so to disable that feature you need to do the following. Plug the modem into your Windows PC, install the Telstra Mobile Broadband software when it prompts you to. Once it's installed and the device has been discovered and it's ready to connect (Green Connect Now button is visible) go to the Tools menu, then Options, then Account tab, down the bottom you will see a tickbox called "Disable SWOC", tick that box, then click the Apply button, then OK to exit. Unplug the device from your PC and plug it into your Routerboard and then it should work fine. I can't include the image I have for information about the lights on the modem as attachments aren't allowed, but basically you want the power light to be solid BLUE and once it's connected to the network you want the data light to be solid GREEN, this indicates a connection to the LTE network, so faster speeds. I hope this has been useful to somebody J Regards Paul