Digi PortServer/8 User Manual page 16

Modems
The easiest way to connect modems is to use Digi's RJ-45 to DB-25 straight-through cables,
which offer full 10-pin connections for full modem control. (You may find ten-pin RJ-45
connectors difficult to find in the retail market). Here are the choices and part numbers:
24 Inch Cables
48 Inch Cables
If you wish to build your own modem cables, follow the diagram below. Cables must be shielded
to remain in compliance with FCC certification requirements, and the shield should be con-
nected to Chassis Ground (GND) at one end of the cable run.
Full 10-Wire Modem Cable
Pin 10
Pin 1
Now connect the modem(s) to the other ports as previously described, plugging the RJ-45 or RJ-
11 connectors from the modems into the appropriate sockets in the back of the PortServer. Again,
make sure the power is off on the PortServer and the modems!
If you want to use 8-pin RJ-45 to DB-25 adapters, a software feature called ALTPIN has been
incorporated into the PortServer software to swap the DCD and DSR signals. This makes DCD
available on pin 1 of an 8-pin RJ-45 connector. See Altpin on page 97.
Page 8 Ÿ Quick Start
DB-25 Male
61020024
61020048
RJ-45 - 10 Pin
Signal Pin
RI 1
DSR 2
RTS 3
GND 4
TxD 5
RxD 6
SG 7
CTS 8
DTR 9
DCD 10
( = Cable Shield)
DB-25 DB-9 Male
Female
61030024 61070024
61030048 N/A
DB-25 Male
Pin Signal
22 RI
6 DSR
4 RTS
1 GND
2 TxD
3 RxD
7 SG
5 CTS
20 DTR
8 DCD