Hi, I have a RB411 and I have a problem with it. When I put power it start up, the lights switch on and I ear the first single beep and also the second double beep after some seconds but if I connect the ethernet to PC there is no connection, also winbox not find anything. Please can you help me? Do you think the ethernet of board is broken?
Thank you
What exactly is “no connection”? Not even ethernet lights? That wouldn’t be good sign. Or only on higher level, i.e. you can’t connect to router? If you’re sure that it’s not just misconfiguration and you didn’t lock yourself out, or even if it is, RB411 is good old router with serial port, so you can use that to see what’s happening.
Thank you for answer. I mean Windows say Network cable unplugged.
How can I use serial? There is a wiki for this?
You need to acquire USB to serial hardware dongle, optional gender changer depending on dongle, and puTTY or equivalent software package.
Ok, and then where can I find the commands to understand if ethernet is just disabled or is died?
In case ethernet is died there is a way to add an ethernet port to the board?
I’d start with: /interface ethernet print detail
You can’t add much to RB411, it has only one MiniPCI slot and I’ve never seen ethernet adapter for that. And even if it does exist, it would be probably expensive rarity, several times more expensive than replacement RB411. Also not necessarily supported by RouterOS. And finally, RB with only one ethernet and nothing else doesn’t sound very useful.
I’m having problem with the serial.
I use putty, set the parameters (115200 bit/s ecc…), Set the correct COM port but on putty I have just a black screen…
What is wrong??
Did you connect it after RB booted or before? Did you try to press Enter? I’m guessing you probably did, but for the lack of better ideas..
I connect after RB boot and also before.
Yes I press Enter…
Have you tried with baud rate = 9600
I try also 9600 but nothing…
The board is died??
The blue light is on and also the first led near the serial port come up when it turn on…
Is it possible I use a wrong cable?
There are specific cable to use or a simple serial cable?
you need null modem cable (where rx/tx pins are crossed, ground connected)
How can I know if my cable is null modem cable?
You wrote that you have beep and double beep, that sounds like live working router.
Cable: https://wiki.mikrotik.com/wiki/Manual:System/Serial_Console#Serial_Console_Configuration
Yes it do a first beep and then after some seconds a double beep.
Ok my cable is not null, I will try to modify it. Do you have some suggestions to do it?
It depends on different factors, how fast you need it, how skilled you are, what components and tools you have available, how lazy you are, etc. 
I bought one so long ago that I don’t even remember when it was, and it works great ever since.
You can buy small male/female plug to put on the end of your USB to serial adapter that will do the same thing without having to rewire a cable.
Ok I create my null modem cable and now I’m on console.
This is the output i get:
[admin@Slave] /interface ethernet> print detail
Flags: X - disabled, R - running, S - slave
0 name="ether1" mtu=1500 l2mtu=1526 mac-address=00:0C:42:4F:EC:xx arp=enabled auto-negotiation=yes full-duplex=yes speed=100Mbps
[admin@Slave] /interface ethernet> monitor ether1
status: no-link
auto-negotiation: done
rate: 100Mbps
full-duplex: no
[admin@Slave] /interface ethernet> monitor ether1
status: link-ok
auto-negotiation: done
rate: 100Mbps
full-duplex: no
[admin@Slave] /interface ethernet> print detail
Flags: X - disabled, R - running, S - slave
0 R name="ether1" mtu=1500 l2mtu=1526 mac-address=00:0C:42:4F:EC:74 arp=enabled auto-negotiation=yes full-duplex=yes speed=100Mbps
This means ethernet is up? So why it not work?
It looks like the router thinks that it does work.
You can try if it sees some packets (/tool torch interface=ether1). Or try some communication from router, add address, try to ping something, check if there’s anything in “/ip arp”.
Or reset everything (/system reset-configuration no-defaults=yes) to get blank config and if it doesn’t work even after that, then I’m affraid that I’m out of ideas.