9 pin D-SUB female connector at the UPS
The Tripp Lite OmniPro 675 is a line-interactive UPS intended to protect desktop workstations and servers. Its rear-panel DB-9 female port provides simple contact-closure signalling — no serial data protocol — to power-management software running on the connected host. The interface carries two status signals (line-fail and low battery) and an inverter shutdown input; a proprietary Tripp Lite cable (part 73-0724) is required to connect the UPS DB-9 to the host PC’s DB-9 serial port. The same interface is shared with the OmniSmart 300, 450, and 675 PNP variants.
| Pin | Description |
|---|---|
| 1 | Common/Negative |
| 2 | External inverter shutdown, positive side |
| 3 | line fail, normaly open contact |
| 4 | return/external inverter shutdown negative side |
| 5 | line fail, normaly closed contact |
| 6 | low battery, positive side (2 minute warning) |
Notes
The DB-9 connector on the UPS chassis is female (DE-9F). Only six of the nine pins are assigned; pins 7, 8, and 9 carry no defined function on this model. A proprietary Tripp Lite PowerAlert cable is required; standard straight-through or null-modem cables are not suitable. The OmniPro 675 manual directs users to contact Tripp Lite Customer Support for detailed wiring information.
Signals
- Common/Negative — signal ground reference for all contact-closure circuits (pin 1)
- External inverter shutdown, positive side — applying a signal here commands the UPS inverter to shut down (pin 2)
- Line fail, normally open contact — closes when mains AC supply fails (pin 3)
- Return/external inverter shutdown negative side — return path for the shutdown input circuit (pin 4)
- Line fail, normally closed contact — opens when mains AC supply fails (pin 5)
- Low battery, positive side — asserts approximately two minutes before battery exhaustion (pin 6)
- Pins 7, 8, 9 — function unknown