From 1 is a interface for RS-232 from DB-9S (Female) to RJ11 to telephone cable to RJ11 to DB-9P (Male). It is not known whether this is any type of standard. Note that if this is accidentally connected to a telephone, then one telephone wire is grounded, and TXD and RXD are no connect. Everything should survive.
6 pin RJ11, RJ14 female
connector at the phone and wallet socket (Jack).
6 pin RJ11, RJ14 male
connector at the cable (Plug).
DB9S (female pins) to jack:
| RJ11 | DB9S | Function |
|---|---|---|
| 1 | NC | - |
| 2 | 2 | RXD |
| 3 | 5 | GND |
| 4 | NC | - |
| 5 | 3 | TXD |
| 6 | NC | - |
DB9p (male pins) to jack:
| RJ11 | DB9P | Function |
|---|---|---|
| 1 | NC | - |
| 2 | 3 | TXD |
| 3 | NC | - |
| 4 | 5 | GND |
| 5 | 2 | RXD |
| 6 | NC | - |
Phone cable, please note that this is a crossover cable, with pins 1 and 6 not used:
| RJ11 | RJ11 |
|---|---|
| 1 or NC | 6 or NC |
| 2 | 5 |
| 3 | 4 |
| 4 | 3 |
| 5 | 2 |
| 6 or NC | 1 or NC |
Here is a variation that is also used. It provides two grounds:
DB9S (female pins) to jack:
| RJ11 | DB9S | Function |
|---|---|---|
| 1 | NC | - |
| 2 | 2 | RXD |
| 3 | 5 | GND |
| 4 | 5 | GND |
| 5 | 3 | TXD |
| 6 | NC | - |
DB9p (male pins) to jack:
| RJ11 | DB9P | Function |
|---|---|---|
| 1 | NC | - |
| 2 | 3 | TXD |
| 3 | 5 | GND |
| 4 | 5 | GND |
| 5 | 2 | RXD |
| 6 | NC | - |