Problems with ethernet ports on HLK-7628n - Page 1
Forum section: electronics / beginners

author: frich
author_rank: Contributor
timestamp: March 23, 2025, 08:46:47 pm
content: Helloi have a project going where i am trying to connect a Hi-Link HLK-7688N to and ethernet port on a Cisco switch, to be able to add a WiFi access point to the network.i have made around 170 of these modules before using a mini router from elecom with great success, unfortunatly the router for that is not being manufactured anymore.so i am trying out this WiFi module from Hi-Link due to the small form factor.the setup is fairly strait forward, with the WAN port of the HLK-7628N connected to an ethernet port on a Cisco switch running the local network, and then i can connect on the WiFi with a tablet, saving me the need to use a laptop and a long cable.the problem i am having, is that i cannot seem to get the connection working on either the WAN port or on any of the LAN ports on the HLK-7628N.the WiFi part works fine, but when i try to connect the ethernet to a laptop i just get unidentified network.i have tried swapping the wires on the ethernet in any configuration i could think about, and i have tried to add a 1k resistor connected to ground from each connector.what i am mainly wondering is, am i missing something in my setup ?? do i need something between the HLK-7628N and the ethernet port ?or is it a matter of software ? (the HLK-7688N is running OpenWRT on a MT7628AN chip)i have attached the user manual and a pinout picture with the connections i have used highlighted with a green circle (2x gnd, 2x 3,3V and the 4 ethernet pins)

author: jwet
author_rank: Frequent Contributor
timestamp: March 25, 2025, 05:35:38 pm
content: I saw this got no responses and was curious.I looked up the data sheet on the module. Its not clear but I think this needs magnetics between the module and the RJ45. The eval boards that have ethernet connectors seem to include magnetics. Do you have magnetics?Its amazing that you can get that for a few dollars these days!

author: thm_w
author_rank: Super Contributor
timestamp: March 25, 2025, 11:22:56 pm
content: So no other mini routers exist that will do what you want?There is a demo board here:https://www.aliexpress.us/item/3256802655253596.htmlHave you hooked up the PHY LEDs at all?Do you have any schematic or this is all hand wired?

author: frich
author_rank: Contributor
timestamp: March 26, 2025, 07:14:26 am
content: see this is where my skillset realy goes to "beginner"i normally work between 12V and 36KVno i do not have any magnetics, i have noticed some on diagrams i have found online. but i do not know what the importance of them are.i assumed they where just used to reduce noise and create a barrier for high frequency spikes, since all the diagrams i found with them, they were internally in the RJ45 connector.i am not planning on using an RJ 45 connector, the plan is to solder the wires directly.something like the attached picture ? (NS0013)cant seem to find this part easy to get in denmark, but i can get a Bourns PT61018AAPEL-S, would that work ?https://uk.rs-online.com/web/p/lan-ethernet-transformers/1345650?searchId=d3a48c61-f4f0-4f57-b13e-8b34f159bef2&gb=sbut if i think about it when looking at the attched picture of an RJ45 connector, that has these coils internally it does make a bit of sense, even thou i am no where near understanding the whole thing

author: frich
author_rank: Contributor
timestamp: March 26, 2025, 07:29:20 am
content: have been using different routers in the past for this, first i used an ASUS, and then later an Elecom (attached picture)these came as a consumer good that i stripped and used the board from.unfortunatly they are kinda hard to come by these days, last time i go 50 directly from a friend in Japan, but he cannot get them from elecom anymore (not produced anymore).i have tried with a Skylab SKW75 for testing, and it worked, but that one is no longer in production either.at the same time i tried with a Skylab SKW103, but i had the same problem as i do not with not getting the WAN port to work. (assumed it was just a bad part, since the SKW75 worked)so decided to try something elsethat ended up with the Hi-Link, but ran into the same problem as with the SKW103, so then i must be missing somethingi havent played with the PHY LEDS at all yet, only been trying to get the fuctionallity to work, then i will start looking into that. i want to have 3 LEDs, power, link and activity.no diagrams at all yet, not realy proficient in the different electronics programs, i guess i need to, since if i get this working i plan on getting PCB's made for it.initially i will most likely just make a couple of prototype boards using fusion360 (yes i know definatly not the right tool)setup is not complicated thou, it is a special industry connector that holds 24VDC and Ethernet, then wired to a buck converter and then the router. (attached pictures of the finnal tool with Elecom router)

author: frich
author_rank: Contributor
timestamp: March 26, 2025, 06:20:06 pm
content: small updatemanaged to find an old board with a LAN transformer.desoldered it and connected it up to the HLK-7628 board.that seems to have done the trick, so was definatly that missing, just need to read up on the different resistors and capacitors.and figure out how i get OpenWRT to do as i want it to