UPS Signal Name | DB-9 Male (UPS end) | DB-9 Female (PC end) | PC Signal Name |
TX / AC Fail | 2 | 2 | Rx, Received Data |
RX / Shutdown | 1 | 3 | Tx, Transmitted Data |
Common | 9 | 5 | GND |
DB 9 PC Male | UPS DB 9 Female | Comment |
1 & 2 | 2 | RX?? Short Pins 1 & 2 on PC side connect to Pin 2 on UPS side |
3 | 1 | TX ?? |
4 | N/C | No Connection |
5 | 9 | GND |
6 | N/C | No Connection |
7 & 8 | N/C | Short Pin 7 & 8 on PC side. |
APC Pin | USB Pin | Description |
---|---|---|
1 | 1 | USB +5V (red wire) |
4 | shield | chassis ground |
7 | 4 | USB GND (black wire) |
9 | 2 | USB Data- (white wire) |
10 | 3 | USB Data+ (green wire) |
UPS Pin | UPS signal | Description |
---|---|---|
1 | USB_VCC | decoupled with a ferrite, and protected with a 6.2V zener on the PCB side |
2 | ON_BATT | (active high) - Logic 1: 12V via 3kohm resistor, Logic 0: 0V via open collector of 2N2222 to gound |
3 | Lo_BATT | (active low) - Logic 1: 12V via 3kohm resistor, Logic 0: 0V via open collector of 2N2222 to gound |
4 | GND | direct connection, no decoupling |
5,6 | USB TST (NC) | No physical connection |
7 | GND | decoupling via ferrite |
8 | INVSD | Active high to base of a 2N2222 (resistor input -> base: 3kohms, resistor base -> gnd: 1kohms) |
9 | USB Data- (negative) | Protected with 47ohms resistors, ferrite |
10 | USB Data+ (positive) | Protected with 47ohms resistors, ferrite |