A-4
Serial Port Pin Assignments
The DB-9 serial port, see
Figure A-3
, located on the rear panel is used to connect the
RoamAbout R1 to an ISDN TA or PSTN modem. The pin assignments used to connect to
this port are provided in the following tables.
Figure A-3: DB-9 Serial Port Pin Numbers
4
Tip
1,2,5,6
Rx+
EIA
Circuit
CCITT
Signal
Description
R1 DB9
DTE Pin #
PC DB9
DTE
Pin #
Modem
DB25
DCE
Pin #
Signal
Direction
DTE-DCE
CF
109
DCD
(Data Carrier
Detected)
1
1
8
<------
BB
104
RxD (Received
Data)
2
2
3
<------
BA
103
TxD
(Transmitted
Data)
3
3
2
------>
CD
108.2
DTR
(Data Terminal
Ready)
4
4
20
------>
AB
102
SG
(Signal Ground)
5
5
7
-------
CC
107
DSR
(Data Set Ready)
6
6
6
<------
CA
105
RTS
(Request-to-
Send)
7
7
4
------>
CB
106
CTS
(Clear-to-Send)
8
8
5
<------
CE
125
RI (Ring
Indicator)
9
9
22
<------
RJ-11 Pin Assignments
