I have an old Tripp-Lite UPS (SU2200RTXL2UA) which I need to communicate with via it's RS232 Port (this model doesn't have a USB port). I'm trying to figure out which Serial NUT driver would be most appropriate to receive communications from this UPS. The serial protocol is very simple, as explained by this excerpt from the user manual below:

Dry contact communications are simple, but some knowledge of electronics is necessary for configuration. The DB9 port's pin assignments are shown in the diagram. If the UPS battery is low, the UPS sends a signal by bridging pins 1 and 5. If utility power fails, the UPS sends a signal by bridging pins 8 and 5. To remotely shut down the UPS, short pin 3~pin 9 for at least 3.8 seconds.

When checking the list of available drivers for Tripp-Lite UPSs, I didn't see any Serial ones listed at all my model (or similar ones in the series). Are there any other generic serial UPS drivers that that would work for this scenario? I mainly just want to capture the signal from pins 8 and 5 being bridged so I can execute a script to shut down some servers which are attached.

NOTE: I'm using NUT with an Ubuntu 18.04 LTS server and a NAS running NAS4FREE (FreeBSD).

EDIT: After reviewing the NUT manual, it appears that the genericups driver with upstype=5 is the appropriate configuration that matches my UPS's RS232 pinout. Now, I just need to figure out how to set it up on my NAS through the GUI I'm using NAS4FREE.

1 Answer 1


Correct me if I am wrong but I believe that your UPS is not compatible with the NAS. You may need to get a different one.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .