I try to attach 80 dcoms usb to my mikrotik router but it can only recognize 20 ports
how can increase that number?
There’s probably hard limit on number of LTE interfaces or USB devices in ROS.
Also that’s quite crazy! What’s your use case to have 80(!!) LTE modems connected to a single ROS?
There is no way there will be enough bandwidth for all of them to run at the same time unless you also added like 10 USB host adapter cards (imagining one of these mining motherboards full of USB host adapters connected to 80 LTE modems… just CRAZY)
This may help explain the issues you are running into.
https://acroname.com/blog/how-many-usb-devices-can-i-connect