====== RS-232 connections ======

9 pin 'D' Connector.

^ Pin ^ Signal ^ Direction ^ Description ^
| 01 | DCD | In | Data Carrier Detect |
| 02 | RxD | In | Receive Data |
| 03 | TxD | Out | Transmit Data |
| 04 | DTR | Out | Data Terminal Ready |
| 05 | GND | - | Ground |
| 06 | DSR | In | Data Set Ready |
| 07 | RTS | Out | Request To Send |
| 08 | CTS | In | Clear To Send |
| 09 | RI | In | Ring Indicator |