### RJ-45 8-Pin to Modem (ALTPIN option)

10-pin RJ-45 plugs may be difficult to obtain in the retail market; therefore, most Digi device driver software incorporates an optional feature called ALTPIN, which swaps the logical functions of DSR (Data Set Ready) with DCD (Data Carrier Detect).

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).

8-Wire Modem Cable for use with ALTPIN Configuration

RJ-45 (Digi End) |  | DB-25 Male (Modem End)
--- | --- | ---
Signal | Pin | Pin | Signal
DCD | 1 | connected to | 6 | DCD
RTS | 2 | connected to | 4 | RTS
GND | 3 | connected (via shield) to | 1 (or shell) | GND
TxD | 4 | connected to | 3 | RxD
RxD | 5 | connected to | 2 | TxD
SG | 6 | connected to | 7 | SG
CTS | 7 | connected to | 5 | CTS
DTR | 8 | connected to | 20 | DTR

If you wish to build an 8-wire modem cable for a Digi RJ-45 port, use an 8-pin RJ-45 plug wired as shown in the diagram.

ALTPIN is not supported under Windows NT when the ports are to be used with the Remote Access Service (RAS) or any application that requires RI, DCD, and DSR. Use the full 10 wire modem cable in these cases.

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