Specifications

Table Of Contents
Chapter 5 EIA-232: RJ-45 to DB-25 25
RJ-45 8-pin to modem (ALTPIN option)
The following table shows how to build an 8-wire modem cable using an 8-
pin RJ-45 plug. This cable supports the Digi ALTPIN option when plugged
into a Digi RJ-45 serial port.
8-Wire modem cable supporting ALTPIN option
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).
ALTPIN is not supported for the PortServer product under Windows NT.
Use a full 10-wire modem cable in this case.
RJ-45
(Digi end)
DB-25 male
(modem end)
Signal Pin Pin Signal
DCD 1 connected to 8 DCD
RTS 2 connected to 4 RTS
GND 3 connected (via shield) to 1 (or shell) GND
RxD 5 connected to 3 RxD
TxD 4 connected to 2 TxD
SG 6 connected to 7 SG
CTS 7 connected to 5 CTS
DTR 8 connected to 20 DTR