These diagrams are reverse engineered from the CheckUPS source.
Various examples use 10 kΩ pull up resistors, but this doesn't work with all
serial ports, so I use 4700 Ω instead.
This cable is probably obsoleted.
Wiring shutdown to DTR isn't a good idea anyway.
DTR -----------> Shutdown
1
TXD -----------+
|
RTS ----+ |
| |
+++ +++
| | | |
+++ +++
| |
DCD ----* |
| |
RXD -----------*
| 5 | 3
o / o /
/ /
* *
| |
GND ----*------+
4
1 = Shutdown
3 = Low Mains
4 = GND
5 = Low Batt
RTS -----------> Shutdown
1
DTR ----*------+
| |
+++ +++
| | | |
+++ +++
| |
DCD ----* |
| |
CTS -----------*
| 5 | 3
o / o /
/ /
* *
| |
GND ----*------+
4
Below a cable with a DB-25 at the PC side;
PC UPS
4 ----------- 1
5 ----*------ 3
|
+++
| | 4k7
+++
|
20 ----*
|
+++
| | 4k7
+++
|
8 ----*------ 5
7 ----------- 4
And one with a DE-9
PC UPS
7 ----------- 1
8 ----*------ 3
|
+++
| | 4k7
+++
|
4 ----*
|
+++
| | 4k7
+++
|
1 ----*------ 5
5 ----------- 4
The resistors are mounted inside the connector shell at the PC side.
The shield is connected to the connector shell at both sides of the cable.
The usual disclaimers apply.