19
COMMUNICATIONS

COMMUNICATIONS INTERFACE PORT

The UPStation GXT 2U UPS has a standard DB-9 serial port female con-
nector located on the rear of the UPS unit. Several signals are provided
on this port and are assigned as follows:
* Maximum voltage and current on pins 1, 7, 8, and 9 is 60VDC; 10.0 mA.

PINS 4 & 5 - REMOTE SHUTDOWN ON BATTERY

1. This pin is functional only when the UPS is in battery mode. If the
UPS is being powered by the utility, Pin 4 will ignore any signal on this
pin.
2. Pin 4 requires a 5-12 VDC signal to shutdown. This normally comes
form the serial port using Liebert’s contact closure cable. It cannot be
used with just a contact closure unless the relay is used to switch a
voltage source. A 5-12 VDC signal for 1.5 seconds or greater is
required to signal a shutdown. Signals for less than 1.5 seconds will
be ignored. After Pin 4 receives a shutdown signal for 1.5 seconds,
the command cannot be canceled.

Pin Assignment Description

1 Low Battery (open collector)
2 UPS TxD (typical RS-232 levels)
3 UPS RxD (typical RS-232 levels)
4 Remote Shutdown (5-12VDC, 10-24 mA max); battery operation
5 Common
6 Remote Shutdown (short to pin 5); all modes of operation
7 Low Battery (open emitter)
8 Utility Fail (open emitter)
9 Utility Fail (open collector)

Pin Assignment Collector to Emitter*

54321
6789
(-)
(+)
330 Ohms
Open
Collecto
r
Open
Emitter