Using an 8-pin RJ-45 plug, the following cable wiring supports most serial terminals or printers with either software or hardware handshaking using the Digi ALTPIN option. This cable is valid with any Digi RJ-45 serial port.
Most terminals and printers use Data Terminal Ready (DTR) for Ready/Busy hardware handshaking. The cable shown supports this method.
| RJ-45 8-pin (Digi End) |
DB-25 Male (Terminal/Printer) |
|||
|---|---|---|---|---|
| Signal | Pin |
Pin |
Signal |
|
|
DCD* |
1 |
connected to |
4 |
RTS |
|
RTS |
2 |
connected to |
5 |
CTS |
|
GND |
3 |
connected (via shield) to |
Shell |
GND |
|
TxD |
4 |
connected to |
3 |
RxD |
|
RxD |
5 |
connected to |
2 |
TxD |
|
SG |
6 |
connected to |
7 |
SG |
|
CTS |
7 |
connected to |
20 |
DTR** |
|
DTR |
8 |
connected to |
8 and 6 |
DCD and DSR*** |
* ALTPIN must be turned on for pin 1 to be DCD. When ALTPIN is
enabled, DCD becomes available on pin 1 of an 8-pin RJ-45 connector
(equivalent to pin 2 of a 10-pin connector).
** Okidata Printers may use SSD (pin 11) instead.
***Some printers require DSR. If DSR is required, it should
be either wired or the printer set to ignore DSR (DSR Invalid).
Important: Other terminal or printer manufacturers may use different methods of flow control. Consult your printer documentation for specific wiring requirements.