Zyxel NR5103E refuses to connect to 5G - V1.00(ACBJ.0)b12 - August 2023.

[Fabien01]

Hello All,

It seems the latest versions of the Zyxel NR5103E ( V1.00(ACBJ.0)b12 ) for Home Broadband supplied as of August 2023 are still faulty and still unable to catch a 5G signal from any surrounding 5G/5G-NSA enabled mast.

After convincing (with a lot of pain) Three support that the original kit/unit they had sent, when I signed up 3 weeks ago, was faulty, I am now on my replacement Three supplied 5G Hub (NR5103E) received yesterday and the problem is evidently still the same, connecting only to LTE-A (never getting onto NR5G-NSA or just temporarily and then dropping back to LTE-A).

I am based in London and my area is fully covered by 5G from Three/EE/Vodafone/O2.

I also use another 5G router that my neighbour lent me for testing (that he himself uses as backup), a Huawei H112-370 and that one connects to 5G no problem at great speeds (with my same Three sim card), when my NR5103E struggles to get 20-30 Mbps even on 4G/LTE (expecting no less than 150 Mbps on 4G in my area and way above 400Mbps on 5G).

No amount of manual band selection permutations (in Network Setting/Broadband/Cellular Band) or reboots or factory resets will do, theses units are just faulty (or I just happen to have received two faulty ones??!).

* This is the cell tower that the Huawei H112-370 connects to (200m away, line of sight):
Cell_ID: 3402311

Physical Cell ID/PCI: 149

PLMN (MCC/MNC): 23420

Region/TAC: 1062

RFCN: 99

This is the cell tower that the Zyxel NR5103E is bent on connecting to:
Cell_ID: 12999260

Physical Cell ID/PCI: 247

PLMN (MCC/MNC): 23420

Region/TAC: 5126

RFCN: 9360, 1392, 99

This is reflecting extremely poorly on Three.

Are there here any users who are in London with the same problem?

When can we expect the units to be fixed (either firmware update or new hardware)?

Could someone on Three Support also investigate the problem with the router connecting to the wrong mast/cell tower?

[Anvil_Iron]

A quick look on the locations of these masts on Cellmapper has the Zyxel connecting north of the Thames near Gunnersbury Park which is a long way from the mast the Huawei is connecting to in Putney.

With Cellular band selection set to auto, what do the two routers select?

Which APN do the two routers use?

With the router SIM in a phone does it connect to 5G? What APN is it using?

Unfortunately, Cellular Lock has been disabled on the Zyxel router which would allow selecting the base station to lock to by Physical Cell ID.

[Fabien01]

* Which APN do the two routers use?
Zyxel: It seems the defaults, when set to Mode Manual, for APN, Auth Type and PDP are : 3internet, None and IPv4 respectively...which looks correct. So leaving the Mode set to Auto.

[Anvil_Iron]

Things to try:

1. Leave APN mode in manual and use Three.co.uk instead of 3internet. Apply settings and restart router. If not working, switch back to 3internet and leave manual APN mode.

2. Disable Band Auto Selection and only select B1, B3 & n78 removing B28. Apply settings and restart router. This may force the router to find a closer mast and connect at 5G.

3. If 2 didn't work, select B20 & B28. Apply settings and restart router. This may give better 4G speeds.

Leave PLMN Auto Selection enabled.

[Fabien01]

Thank you Anvil_Iron. I've had some success with getting the router to connect to 5G (managed to lock onto same local tower as H112-370). I will post the details (bands, APN, etc) in another post soon.
I say 'some success' because the connection speed is still quite low (the 5G indicator in router Interface Status won't show more than 2 bars) so am still experimenting.

[Fabien01]

Hi Anvil_Iron and thank you for your message.

* With Cellular band selection set to auto, what do the two routers select?

Zyxel: B28, B3, B1

Huawei: I cannot find a way to see that info for this router...would expect to see n78 in the list...will look again.

* Which APN do the two routers use?
Zyxel: (in Network Setting/Broadband/Cellular APN): 1 Enable, Mode: Auto, APN: N/A, Auth Type: N/A, PDP Type: N/A... APN, Auth Type and PDP Type seem wrong...was expecting to see here: Three.co.uk, None and IPv4 respectively...?...could/should try to set this manually?

Huawei: I cannot find a way to see that info for this router...should be in Profile Management...will look again.

*With the router SIM in a phone does it connect to 5G? What APN is it using?
The Three sim card for the router also operates fine and connects to 5G no problem in my iphone (getting no less than 80 Mbps). I will check the APN later on today again.

* Unfortunately, Cellular Lock has been disabled on the Zyxel router which would allow selecting the base station to lock to by Physical Cell ID.
There is a toggle button in Network Setting/Broadband/Cellular PLMN which turns 'PLMN Auto Selection' ON/OFF. Would that help?