APC SU1400XLT User Manual download pdf (Page 79)

Apparently, all APC voltage-signalling UPSes with DB9 serial ports have the same signals on the output

pins of the UPS. The difference at the computer end is due to different cable configurations. Thus, by

measuring the connectivity of a cable, one can determine how to program the UPS.

The signals presented or accepted by the UPS on its DB9 connector using the numbering scheme listed

above is:

UPS Pin Signal meaning

1 <- Shutdown when set by computer for 1-5 seconds.

2 -> On battery power (this signal is normally low but

goes high when the UPS switches to batteries).

3 -> Mains down (line fail) See Note 1 below.

5 -> Low battery. See Note 1 below.

6 -> Inverse of mains down signal. See Note 2 below.

7 <- Turn on/off power (only on advanced UPSes only)

Note 1: these two lines are normally open, but close when the

appropriate signal is triggered. In fact, they are open collector

outputs which are rated for a maximum of +40VDC and 25 mA. Thus

the 4.7K ohm resistor used in the Custom Simple cable works

quite well.

Note 2: the same as note 1 except that the line is normally closed,

and opens when the line voltage fails.

The Back-UPS Office 500 signals

The Back-UPS Office UPS has a telephone type jack as output, which looks like the following:

Looking at the end of the connector:

6 5 4 3 2 1

_____________

| . . . . . . |

| |

| |----------|

|__|

It appears that the signals work as follows:

UPS Signal meaning

1 (brown) <- Shutdown when set by computer for 1-5 seconds.

2 (black) -> On battery power

3 (blue) -> Low battery

4 (red) Signal ground

5 (yellow) <- Begin signalling on other pins

6 (none) none

Analyses of APC Cables

940-0020B Cable Wiring

Supported

Models:

Simple Signaling such as BackUPS

1 2 ... 74 75 76 77 78 79 80 81 82 83 84 ... 114 115

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APC SU1400XLT User Manual Page 79