Serial Communications Loopback Plug (technically a cable, since various pins loop back, connecting to other pins of the same connector) for the diagnostic testing of serial ports when using PC-check software.
9 pin D-SUB female
connector
| Pin | Name | Description |
|---|---|---|
| 1 | 1-4-9 | |
| 2 | 2-3 | |
| 3 | 6-7-8 | |