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dkong
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Serial console connection to M33G won't work

Wed May 26, 2021 1:34 pm

Hello Mikrotik users,

I have a problem getting my serial console connection to work with my M33G RouterBoard.

I own a RB4011iGS+RM and a CRS326-24G-2S+RM, both of which have a RJ45 serial port which works perfectly. I use a Delock USB to DB9 adapter in my Windows laptop, with a blue Cisco serial cable. Usually, any device with a serial console via RJ45 just works with Putty.

The M33G has me stumped though. It has a DB9 serial console port which just won't work. I've searched on these forums and with Google and found this: https://serverfault.com/questions/97839 ... -rb4011igs
So I bought a Startech DB9 to RJ45 converter where you have to wire the pinout yourself. I messed the first one up, and did it straight through. Now I have another one, which I "rolled" (inverted the pinout), but still my M33G won't respond.

I've tried setting auto-baud under /port, and /system console set 0 disabled=no, but nothing makes a difference. I have another Startech converter under way, to try the crazy pinout referenced here: https://wiki.mikrotik.com/wiki/Manual:S ... erial_port But I believe this is already the pinout that my blue Cisco cable is supposed to have internally, so I assumed I just need a regular or rolled DB9-RJ45 converter.

Can someone please point me in the right direction? My M33G board is a proof-of-concept. I want to order a whole bunch for my company to put them in the field, but I'm kind of hesitant to deploy a product where I can't use the serial console.
 
dkong
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Re: Serial console connection to M33G won't work

Thu May 27, 2021 12:09 pm

Update: I just noticed that the non-rolled RJ45-DB9 converter shows serial output during the boot process, up until the following output:
RouterBOOT booter 6.47.8

RBM33G

CPU frequency: 880 MHz
  Memory size: 256 MiB
 Storage size:  16 MiB

Press any key within 2 seconds to enter setup..
m33 boot from CS1

loading kernel... OK
setting up elf image... OK
jumping to kernel code
Starting...
Starting services...
MikroTik 6.48.2 (stable)
SGGx-RTR1 Login:
After that, it won't respond. Next step will be fiddling with the RouterOS settings until it responds, I guess.
Last edited by dkong on Thu May 27, 2021 5:31 pm, edited 1 time in total.
 
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xvo
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Re: Serial console connection to M33G won't work

Thu May 27, 2021 12:45 pm

At least console should run on the port in question.
 
dkong
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Re: Serial console connection to M33G won't work

Thu May 27, 2021 5:31 pm

@xvo: thanks for your input. I looked into the RouterOS config more carefully but based on my understanding so far, everything is properly configured as follows:
[admin@SGGx-RTR1] > /system console print detail
Flags: X - disabled, U - used, F - free
 0 F port=serial0 channel=0 term="vt102"
[admin@SGGx-RTR1] > /port print detail
Flags: I - inactive
 0   name="serial0" used-by="Serial Console" device="" channels=1 baud-rate=auto data-bits=8 parity=none stop-bits=1 flow-control=none

 1   name="serial1" used-by="" device="" channels=1 baud-rate=auto data-bits=8 parity=none stop-bits=1 flow-control=none
[admin@SGGx-RTR1] >
The result is still the same: the M33G shows serial output during the boot process, up until the login prompt, then it won't respond to keyboard input.
I did notice something interesting though: if I keep the serial cable connected and Putty open, switching the system console from serial0 to serial1 and back to serial0 again gives me another login prompt in my CLI session. So on a fundamental level serial communication does seem to work, it just isn't responding to any keyboard input.
 
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xvo
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Re: Serial console connection to M33G won't work

Thu May 27, 2021 5:47 pm

IIRC when I was trying to make my own db9 to rj45 adapter for CCRs I ended up with only 3 pins connected - TX, RX and GND and it worked fine with the same usb to rj45 serial, that works with other mikrotiks with rj45 port.

But don’t have it at hand at the moment, so can’t help you with exact pinout.

Also try setting baud-rate manually.
 
dkong
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Re: Serial console connection to M33G won't work

Fri Jun 25, 2021 3:45 pm

Thanks for the input again @xvo. A manual baud-rate doesn't make a difference either. At this moment I'm just deploying the box without proper serial support. It can't be a pinout problem as I'm getting console output over serial during the boot process, but as soon as RouterOS is loaded, serial communication stops working.

This can at least be used to troubleshoot a faulty unit, by seeing if it still boots. If it does, I guess we will have to reset the config to default, then load the proper config again if it ever becomes unresponsive.
 
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xvo
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Re: Serial console connection to M33G won't work

Fri Jun 25, 2021 4:34 pm

It can't be a pinout problem as I'm getting console output over serial during the boot process
That don't mean anything, if your input pin is misplaced you won't get any output either if the device is just working normally.
You can check the output by triggering some log entries that have "echo" as an action.

BTW, the pinout that works for me is:

RJ45 DB9 (female)
6 RX - 2 RX
3 TX - 3 TX
5 GND - 5 GND
Rj45-pinout.png
In other words no rx/tx crossover, like on original in the manual:

Image
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