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Serial Port Pin Assignments
Serial Port Pin Assignments
The
Figure B-2. DB-9 Serial Port Pin Numbers
DB-9 Port Pin Assignments
EIA | CCITT | Description | Gateway’s | PC DB9 | Modem | Signal |
Circuit | Signal |
| DB9 DTE | DTE | DB25 DCE | Direction |
|
|
| Pin # | Pin # | Pin # | |
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 | 7 | 7 | 4 | |
CB | 106 | CTS | 8 | 8 | 5 | |
CE | 125 | RI (Ring Indicator) | 9 | 9 | 22 |