25 PIN D-SUB CONNECTOR
| Pin | Name | Description | 
|---|---|---|
| 1 | GND | Ground | 
| 2 | TxD | Transmit Data line | 
| 3 | RxD | Receive Data line | 
| 4 | RTS | Request To Send | 
| 5 | CTS | Clear To Send | 
| 6 | DSR | Data Set Ready | 
| 7 | GND | Ground | 
| 8 | DCD | Data Carrier Detect | 
| 9 | n/c | Not connected | 
| 10 | n/c | Not connected | 
| 11 | n/c | Not connected | 
| 12 | n/c | Not connected | 
| 13 | n/c | Not connected | 
| 14 | n/c | Not connected | 
| 15 | TxC | Connected to TRxCA | 
| 16 | n/c | Not connected | 
| 17 | RxC | Connected to RTxCA | 
| 18 | n/c | Not connected | 
| 19 | n/c | Not connected | 
| 20 | n/c | Not connected | 
| 21 | n/c | Not connected | 
| 22 | n/c | Not connected | 
| 23 | n/c | Not connected | 
| 24 | TEXT | Connected to TRxCA | 
| 25 | n/c | Not connected | 
Contributor: Joakim Ögren
  Source:
  Technote HW19: Pinouts at Apple Technical Notes
  Copyright © The Hardware Book Team 1996-2001.
  May be copied and redistributed, partially or in whole, as appropriate.
 Document last modified: 2000-07-09