TP-Link T2U Plus - 5GHz band

Question

Just picked up this TP-Link wireless adapter:

Archer T2U Plus

I plugged it into one of my desktops, and it was not detected. A quick google search lead me here:

TP-Link AC600 Archer T2U Nano driver for Ubuntu 18.04

I installed dkms and the drivers, and the adapter started working. I was able to connect to my network no problem.

I then realized that this adapter was only operating on the 2.4GHz band. I renamed my SSIDs to identify the 2.4GHz and 5GHz bands (previously they were named the same, allowing the client to decide which band to use), and sure enough, the adapter was not able to find the 5GHz network. It found the 2.4GHz network fine.

I tried running the same installation on the following systems:

• Ubuntu 20.04 - Kernel version 5.4.0-67-generic
• Ubuntu 18.04 - Kernel version 4.15.0-137-generic

Both had the exact same outcome.

I am doing something stupid. What is it? Others either got this working, or didn't notice that the 5GHz band was missing.

lsusb outputs:

20.04:

Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 046d:c52b Logitech, Inc. Unifying Receiver
Bus 001 Device 008: ID 2357:0120 TP-Link 
Bus 001 Device 006: ID 0079:0006 DragonRise Inc. PC TWIN SHOCK Gamepad
Bus 001 Device 005: ID 2563:0575  
Bus 001 Device 004: ID 0079:0006 DragonRise Inc. PC TWIN SHOCK Gamepad
Bus 001 Device 002: ID 0bda:5411 Realtek Semiconductor Corp. 4-Port USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

18.04:

Bus 002 Device 003: ID 058f:6366 Alcor Micro Corp. Multi Flash Reader
Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 04f2:b2fa Chicony Electronics Co., Ltd 
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 003: ID 058f:9410 Alcor Micro Corp. Keyboard
Bus 003 Device 007: ID 2357:0120  
Bus 003 Device 005: ID 1bcf:0005 Sunplus Innovation Technology Inc. Optical Mouse
Bus 003 Device 004: ID 041e:30dd Creative Technology, Ltd 
Bus 003 Device 002: ID 05e3:0610 Genesys Logic, Inc. 4-port hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Note: For some reason, the adapter did not get assigned a name on 18.04. Identifier is 2357:0120

Other Note: I have no idea why I am including the output of lsusb, but it seems to be what others have asked for

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Continuing to compile information here:

Can't use 5Ghz band of USB wifi dongle

This person seemed to have the same issue, but his fix seems to be exactly where I started.

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Jags asked for the settings on the router:

2.4GHz:

5GHz:

Output of iwlist chan:

wlx984827b964b3  32 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 52 : 5.26 GHz
          Channel 56 : 5.28 GHz
          Channel 60 : 5.3 GHz
          Channel 64 : 5.32 GHz
          Channel 100 : 5.5 GHz
          Channel 104 : 5.52 GHz
          Channel 108 : 5.54 GHz
          Channel 112 : 5.56 GHz
          Channel 116 : 5.58 GHz
          Channel 120 : 5.6 GHz
          Channel 124 : 5.62 GHz
          Channel 128 : 5.64 GHz
          Channel 132 : 5.66 GHz
          Channel 136 : 5.68 GHz
          Channel 140 : 5.7 GHz
          Channel 149 : 5.745 GHz
          Channel 153 : 5.765 GHz
          Current Frequency:2.412 GHz (Channel 1)

Answer 1

If you have 2.4GHz wireless working but 5GHz wireless is not being detected at all, then it's most likely a configuration issue depending on the router.

So go to your router's Wireless settings for 5GHz, and set it as per following:

(1) Mode: AC Only
(2) Channel: 140
(3) Channel width: 20 MHz
Apply changes.

Note-1: Wireless Channel can be any between supported range of your wireless adapter but keep the Channel width to 20 MHz, and Mode to AC only.

Note-2: You can find out the channels supported by your wireless adapter by: iwlist chan.

Now you may need to reboot router after the above, which depends on the make/model of your router.

If it was a case of router configuration, you would now have a working 5GHz wireless.

Answer 2

Jags's answer helped me a lot, but I did a couple of things differently that I wanted to share in case someone else has the same problem. In my case, I was able to keep the Mode on auto and the Channel Width on auto(or up to 80 MHz which is the limit of my router). For the Channel, everything below 150 worked well for me, but above 150 it wasn’t working at all. Even after those changes, it was still slow to connect when I would start my computer. I fixed that problem by setting manually my IP address (I choose a random IP address that was available and outside of the DHCP range).

My configuration(I did the same thing on two different computers):

• OS: Ubuntu 21.04 and 20.04
• Driver: https://github.com/aircrack-ng/rtl8812au.git
• USB adapter: TP-LINK Archer T2U Plus and TP-LINK Archer T2U Nano

Answer 3

For anyone who's facing problems connecting their Archer rtl88**au (T2U plus in my case) after rebooting their computer, or if you can't connect to the 5GHz band, here's what worked for me and might as well for you -

I followed the instructions given in this github repo down to the letter and it fixed all my problems.