1800 Series User Manual
27
RS-232C
RS-232C serial communication interface is a standard feature that can be
used by authorized service personnel. It is provided through a DB9 female
connector located on the back of the UPS (see “Layout “, page 15). This
interface allows communication between the UPS and a personal computer.
The chart below shows the signals and the connector pinout.
Pin I/O Symbol Description In the UPS
1 This pin not used
2 Input RXD Receive Data
3 Output TXD Transmit Data
4 Output DTR* Data Terminal Ready
5 - GND Signal ground
6 Input DSR* Data Set Ready
7 Output RTS** Request to Send
8 Input CTS** Clear to Send
9 This pin not used
(*) (**) These pins are tied together internally in the UPS. Signals DTR, DSR,
RTS, and CTS are not used.
DB9 Female Connector Outline
(facing connector)
N/C
N/C
GND
TXD
RXD
1
2
3
4
7
6
5
8
9
