Router fails to recognize a live ethernet wire

ZeeWabderer

my ISP provides internet services during power outages. So i connected my armor-g5-nbg7815 to EcoFlow battery and expected to have internet connection, but the router GUI indicates it can't connect to the internet. So then i tried connecting an ethernet cable to the laptop, and it works, and then to a really old Apple Router, and that works too, without a hitch.
So the question is how do I fix my armor g5 to work as expected and how dead is the support for it exactly?

ZeeWabderer

Evidently adding a powered switch, then plugging it as internet→switch→router is a crutch to workaround the problem. The incoming cable at home is also used to carry TV signal, 2 twisted pairs for the internet, 2 for tv. Terminal extracts tv signal from the cable and branches it off, but evidently when power is off TV signal isn't carried at all and that somehow affects the detection of live ethernet cable on this particular router. Likely 2 pairs are not powered at all in this case, or maybe it has something to do with voltages, either way router decides the cable is not live.
A laptop and an old router work fine, so I guess they have different or lousier offline cable detection parameters (or the inverse), so this problem should be solvable via a patch.

The question then is how to correctly report it? This does not seem like the place.

ZeeWabderer

It turns out that simply disconnecting the 2 pairs that do not carry the internet signal works too. Either way, it's likely some sort of physical signal characteristic that is different on the 2 pairs that carry TV signals when they are powered and when they are not which confuses the router into deciding the wire is not live. And as I said an older router and laptop work fine directly. Technically I have solved the problem but I think this still needs to be patched

tonygibbs16

Hello @ZeeWabderer

According to https://www.zyxel.com/us/en-us/products/wifi-router/ax6000-12-stream-multi-gigabit-wifi-6-router-armor-g5/specifications the Armor G5 has a WAN port that works at 100Mbits/1000Mbits/2.5Gbits speeds.

According to https://www.practicalnetworking.net/stand-alone/ethernet-wiring/#:~:text=The%20first%20major%20difference%20is,when%20building%20a%20Crossover%20cable.&text=That%20said%2C%20Gigabit%20Ethernet%20requires%20Auto%20MDI%2DX. Gigabit Ethernet needs all 4 pairs in order to work, ie 8 wires, whereas FastEthernet at 100Mbits needs only 2 pairs of wires.

"The first major difference is the gigabit standards require the use of all four pairs (all eight wires), unlike Fast Ethernet which only utilizes two pairs of wires. As a result, in Gigabit Ethernet, all four pairs must be crossed when building a Crossover cable."

FastEthernet at 100Mbits/s full duplex uses only 2 pairs of wires, but they have to be in specific places in the RJ45 connectors as follows:

"100BASE-TX (with all eight wires) is the commonly used Fast Ethernet specification today. However, it is often (lazily) referred to as simply T. Again, T is meant to refer to the category of Twisted Pair options, and TX is the specific standard that calls for using the pairs at pin-positions 1&2 and 3&6."

So possibly putting the switch in line sorts out the cabling so that the Armor G5 can bring up it's WAN connection.

It is possible that the cabling you have to share TV and Ethernet on the same cable is non standard…

Kind regards Tony

tonygibbs16

Hello @ZeeWabderer

In terms of a patch for the Armor G5, there will not be one from Zyxel as it has passed its End of Development date, see https://webservice.zyxel.com/end-of-life and below screenshot.

If you are not on the latest firmware V1.00(ABSK.8)C0 then you can do a check for the latest firmware as shown below (from the user guide https://download.zyxel.com/Armor_G5_(NBG7815)/user_guide/Armor%20G5%20(NBG7815)_V1.00_Ed6.pdf downloaded from https://www.zyxel.com/uk/en-gb/support/download?model=armor-g5-nbg7815 ):

Kind regards,

Tony