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What are the computer interface port specifications for the SU and SUA Smart-UPS family?


What are the computer interface port specifications for the 3G Smart-UPS family?

Product Line:



All SU, SUA models, All Serial Numbers


APC uses propriatary technology in our serial cables, however some basic functionality can still be had by connecting directly to the serial port on the UPS.
This is called "Simple Signaling"

The computer interface port in SU and SUA Smart-UPS have the following characteristics:
  • Pins 3, 5, and 6 are open collector outputs which must be pulled up to a common referenced supply no greater than +40 Vdc. The transistors are capable of a maximum non-inductive load of 25 mAdc. Use only pin 4 as the common.
  • Pin 2 generates a low to high transition at RS-232 levels when the UPS signals that it is on-battery. Pin 2 is also the RS-232 data output (TXD).
  • The UPS will shut down when a high RS-232 level is sustained on pin 1 for 4.5 seconds. The UPS responds to this signal only after a delay and during a power utility failure (when the UPS is operating on battery). Pin 1 is also the RS-232 data input (RXD).
  • Apply a momentary (approximately 1 second) high RS-232 level to pin 7 to turn on the UPS and any attached loads. A momentary low turns off the UPS and its load. Pin 7 should be unconnected normally.
  • DC operating voltage is available at pin 8.

For more detailed communications information, refer to APC Application Note #181 - "Smart-UPS Communication"

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