User guide

Cables
B-4
Serial Port Pin Assignments
The DB-9 serial port on the rear panel is used to connect the CheetahAccess
Internet Gateway to an ISDN TA or PSTN modem. The pin assignments used to
connect to this port are provided in the following tables.
Figure B-2. DB-9 Serial Port Pin Numbers
DB-9 Port Pin Assignments
EIA
Circuit
CCITT
Signal
Description Gateway’s
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 <------