@Sunshine 

This port has signal when external LTE antenna connected.

Port in the picture below has not signal when external LTE antenna connected.

So I try to connect the same antenna in different ports, and one port has signal, but another port not.

I live in rural areas, there are not sense to check how original antennas works. I have signal only on external antenna on the roof (around -110db RSRP). 

I have received the TL-MR100E yesterday and I hope it will work with my Huawei B618s-22 4G LTE router. I have bought 3 external antennas but they can't be connected to the TL-MR100E because there is no port. The TL-MR100E has two external antenna ports ( X1 and X2 ) which are located at the back of the device, and one internal antenna port ( ANT ). Also, there are three adjustable dipole antennas which are designed to be plugged into the external antenna ports. The dipole antennas get paired with each external antenna port respectively.

I have a few TP-Link TL-MR100 (aka TL-MR3040) 3G travel routers. The back of the router has 2 external antenna ports, one for VHF and one for UHF frequencies. 2.4GHz and 5GHz wifi signals are transmitted through PCB antennas on the sides of the router.

Typical external antennas are of course not compatible with these ports because they're designed for magnetics N female connectors and typical antennas have SMA male connectors.