Quantum fiber c5500xk
Quantum Fiber C5500XK Info
Factory Reset
Here are the docs on how to reset the modem to factory settings: https://www.quantumfiber.com/support/equipment/troubleshooting/modem-reset.html
You can reset the device to factory settings by holding the reset button on the bottom of the unit for 30 seconds. The LED will blink yellow/orange to verify it is resetting. I did this multiple times and it worked every time. However the docs on the page above mention to not reset the C5500XK to factory settings without talking to support?
Transparent Bridge Mode
This modem has the ability to go into Transparent bridge mode. This mode allows you to hook up your own router without having a double NAT situation. According to what I've found when you do enable it you have the option to enable VLAN tagging, or not. If your router doesn't support VLAN tagging on the WAN port you would select VLAN tagging in the modem UI and your router will work, but there are reports that your internet will be a little bit slower. If your router does suppoort VLAN tagging on the WAN port you should select "untagged" on the modem UI and then configure your router to VLAN tag 201 on the WAN port.
This page explains how to enable transparent bridge mode. In there it says to contact support to figure out which VLAN tagging method you should choose; it seems this is a regional setting? When I followed these steps using VLAN tagging and no VLAN tagging my modem would go into a state that didn't seem to work. The LED starts blinking blue which according to This page means it's "Syncing with the network". The LED never seems to go to solid white, which would indicate it was in transparent bridge mode.
I called support and they basically said "this is a new device and sometimes it doesn't work in transparent bridge mode".
Before giving up I figured why not update my router to use thew vlan setting and PPPoE config. After I updated my router I had a public IP from the modem on my router and had internet access. Interestingly The modem is still blinking blue, but it seems everything is working.