Peplink Max antenna ports swapped?


I just purchased 2 Peplink Max Transit devices. I have a SIM card in slot A (top slot) only, B is empty. However if I have antennas on the Main 1A and Aux 1A antenna ports the modem is unable to find any cell towers. Once I swap the antennas to Main 1B and Aux 1B, it finds and connects no problem. I can unscrew the antennas on the B ports and see on the GUI the cell bars drop. Adding antennas to the A ports doesn’t help. Once connected, everything else works fine.

Is this normal behavior? I don’t see anything in the manual. The issue is I am planning on buying a lot more of these for field work and I need to put together some instructions for users. Should I expect this behavior from all of them or is this a bad batch and should be replaced?


Can you edit your post and tell us which flavor of Max Transit… Cat 18, 5G, Duo, etc.

Cat 18 Max Transit device uses different frequencies on different ports and needs all 4 antennas connected


@C_Metz is right. If you having Transit CAT 18 or 5G devices, make sure you have the 4 x antennas connected to the device.

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Oh, I didn’t see that in the manual. The PN I have is MAX-TST-GLTE-G-T-PRM. That does look like the Cat 18 modem. I am using B48 here, so that would make sense why the antennas on B connectors were needed.
Where did you find that information? I looked in the datasheet and manual that I downloaded from peplink and didn’t see that information.

That is from the Telit LM960 hardware manual. Peplink‘s manual wants you to use all 4 ports because you don’t know which frequencies the cell tower will choose at a given time. That Cat 18 modem is meant to use up to 5 frequencies in the downlink and up to 3 in the uplink.

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Thank you for this information, that helped me understand what is going on.

Seems like that could be a labelling improvement for Peplink. With the A and B designation for antennas and SIM card slots, it is very easy to assume that they are related. If they want all 4 antennas connected, maybe just designate the ports as 1,2,3, and 4 without the lettering to imply that they correspond to the SIM slots. The included literature in the box doesn’t even say to connect all 4 antennas.