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E3372 LTE interface blinking in and out of existence. Not power related.

Posted: Wed Oct 05, 2016 10:08 pm
by TrisT
Hi, I just got 6.37.1 on my CRS125-24G-1S-2HnD-IN. I'm using winbox 3.6.
The E3372 is connected to the router. I made a cable out of 2 USB cables and it's now getting power from a USB phone charger alone.
This was happening to me since the beginning and I thought it could be the router cutting the power whenever the E3372 went into LTE and consumed too much - which is why I made the cable. That means the problem is not power related given the router is providing no power at all.
I thought maybe it was a bug since I hadn't updated the router in a while. Updated to 6.37.1 and it's the exact same.
The E3372 connected to a computer through that same cable I made works flawlessly.
In winbox the LTE interface just fazes in and out of existence and after a while completely ceases to exist. The E3372 still blinks as it would if it were working normally.

Why is this happening and what do I have to do to fix it?

Thank you.

Re: E3372 LTE interface blinking in and out of existence. Not power related.

Posted: Thu Oct 06, 2016 10:52 pm
by kima
I have the same problem but with different router.
My hEX working perfectly with E3276 thought the cable, but hAP feels like you described.

I don't think that it's a power issue.

Did you tried to use USB cable with ferrite bead?

Re: E3372 LTE interface blinking in and out of existence. Not power related.

Posted: Fri Oct 07, 2016 12:50 am
by TrisT
I have the same problem but with different router.
My hEX working perfectly with E3276 thought the cable, but hAP feels like you described.

I don't think that it's a power issue.

Did you tried to use USB cable with ferrite bead?
What do you mean by hAP?
I did not, should it matter? I mean it did work fine on a regular windows computer without one.


Also if I may:
I have the same problem but with a different router.
My hEX works perfectly with a E3276 thought the cable, but hAP feels like you described.

I don't think that it's a power issue.

Did you try to use the USB cable with a ferrite bead?

Re: E3372 LTE interface blinking in and out of existence. Not power related.

Posted: Fri Oct 07, 2016 1:04 pm
by kima
From Wiki -
A ferrite bead or ferrite choke is a passive electric component that suppresses high frequency noise in electronic circuits. It is a specific type of electronic choke. Ferrite beads employ high frequency current dissipation in a ferrite ceramic to build high frequency noise suppression devices. Ferrite beads may also be called blocks, cores, rings, EMI filters, or chokes.
Ferrite beads prevent interference in two directions: from a device or to a device.[1] A conductive cable acts as an antenna – if the device produces radio frequency energy, this can be transmitted through the cable, which acts as an unintentional radiator. In this case the bead is required for regulatory compliance, to reduce EMI. Conversely, if there are other sources of EMI, such as household appliances, the bead prevents the cable from acting as an antenna and receiving interference from these other devices. This is particularly common on data cables and on medical equipment.
I don't have a cable with ferrite baed to make tests, but I'm sure it will work.

hAP - RB951Ui-2nD
Also if I may:
Of course you may) It's a little difficult for me to write correctly without proper practice.
I'm sorry about this!

Re: E3372 LTE interface blinking in and out of existence. Not power related.

Posted: Fri Oct 14, 2016 2:21 am
by luzak133
Hello,

I have got the same issue on CRS125-24G-1S-RM with firmware 6.37.1. I use Winbox 3.7 and Huawei E3372s-153 in Hilink mode.

About a year ago I have setup that such hardware configuration an it was working fine. More less two months back I have upgraded a Mikrotik firmware to version 6.32 and that started the problem.
Simply the lte interface on router shows up and after a second it goes away.
So today I got a different modem running in PPP mode and it works just fine. Since I had changed a router configuration to get things working I made a backup and once again tried to get Hilink modem alive (just for exercise)

To the point,
Today I have discovered a very weird behavior of a USB subsystem on a router. It looks like guys at Mikrotik messed up something with USB reset logic !!! It seems that this logic was INVERTED !!!
So if you tell the router to reset a USB power for duration of for example 5 seconds you expect, that router will switch off USB, wait 5 seconds and then get USB up again. But it does exactly opposite actions (at least mine) - switches on USB, waits 5 seconds and then turns off USB !!!
At first I thought that it may be a Winbox issue, but over serial console I had the same error.

Probably that is the cause why the lte interfaces on Hilink (and probably NDIS) are no brought up correctly and are unstable. You can test if this happens also with your hardware. If so I will write to the Mikrotik support team. Please do the following :
1. Connect your modem to the router with USB any way you want (directly, through hub or self made "power injector")
2. Reset a router
3. After reset, connect to router with Winbox and display a list of connected USB devices and a list of LTE interfaces (you will probably not see any LTE interface)
4. Apply USB Power Reset for 60 seconds
5. At this point you should see a new entry on LTE interfaces list and at least two entries on USB devices list (EHCI controller and your modem)
6. Try to use your LTE connection - make a speed test, watch a movie, download something... - LTE should be stable (mine was)
7. After one minute all your transfers should hang and all entries from USB devices and LTE interfaces lists should disappear

Please let me know If you have the same behavior of your router.

Best regards

Re: E3372 LTE interface blinking in and out of existence. Not power related.

Posted: Mon Nov 21, 2016 2:20 pm
by wolfktl
I have the same problem. Tried to add a USB powered hub. LTE air interface does not appear