Mikrotik RB450Gx4 6.42.12 does not load if a cable is connected to it to COM and to UPS (APC). In the process of loading the router, the UPS go crazy, switch to the battery, make self-tests, the router does not load. If i disconnect the COM-cable from the router, it immediately loads normally. It turns out with the cable connected (COM), I can not overload the router.

Are you using the correct cable? APC UPSs do not have a standard pin-out and you cannot just use any old cable without weird things such as this happening.

I know the cable is right. Mikrotik after loading sees UPS normally, reads all indications (voltage, load), but if the router is reboot, then it does not boot normal with the cable, it is necessary to disconnect the cable, the router immediately boot normaly.

Need to set bios correctly to not output anything via serial, will drive serial devices crazy.


Sent from my SM-A520W using Tapatalk

How to do it?
such a feeling that Mikrotik, when booting, sends something to the COM port and tries to boot from it.

Been a while since I did it, i don't have a 450 anymore, but it was in the bios. Connect serial cable, open terminal on computer, restart router, go into bios menu, there was an option to not output a prompt.


Sent from my SM-A520W using Tapatalk

The problem is partially solved.
It was necessary in system-routerboard-settings to prohibit entry to the BIOS menu by pressing any button (configured to press DEL), now the download is normal with the connected cable.
It was not possible to disable the output to the console port of the diagnostic information, there is no such option in the menu, so oops sometimes! behaves not very adequately, but not always.