15
Changing Communication Modes
1.
Find the DIP switches on the back of the UPS (see the drawings
below); then, find DIP switch 4 (see the drawing to the right).
2.
Use a nonmetal object such as a toothpick to move DIP switch 4
from one side to the other; if the UPS is on, it will beep. Make sure
you do not accidentally change the position of another DIP switch.
LI 1020 and 1420
LI 520 and 720
5C. RS232 Communication Mode
When the UPS is in the RS232 communication mode, the pins at the DB9 communication port
perform these functions:
Pin 1:
RS232 Receive Data. Receives incoming RS232 communication data.
Pin 2:
RS232 Transmit Data. Sends outgoing RS232 communication data.
Pin 3:
Normally Open On Battery Contact. A normally open contact that closes 15 seconds
after the UPS switches to battery power.
Pin 4:
Common. The signal ground for all signal pins.
Pin 5:
Normally Open Low Battery Alarm Contact. A normally open contact
that closes during a Low Battery, Near Low Battery, or Low Runtime
alarm. This tells CheckUPS and other shutdown software when to start a
computer shutdown. (You can enable this contact for other alarms; for
more information, call Best Power for document FTS 502.)
Pin 6:
Plug and Play Sense for Windows 95.
Pin 7:
Remote Shutdown. Shorting this pin to common turns the UPS off.
Pin 8:
Unreg12 V isolated source.
Pin 9:
Not Used.
Contacts consist of open collector circuits capable of switching up to +40 VDC 50 mA resistive
load. If you would like to communicate with the UPS without using CheckUPS software, call
Best Power to request document FTS 502.
DIP Switches
DIP Switches
4
3
2
1
RS232
Mode
Extended
Signal Mode