| computer Pin Name | computer Pin Number | Direction | Epson printer Pin Number | Epson printer Pin Name | Description |
| Receive Data (RxD) | 2 | <-- | 2 | Transmit Data (TxD) | |
| Transmit Data (TxD) | 3 | --> | 3 | Receive Data (RxD) | |
| Data Terminal Ready (DTR) | 4 | --> | 6 | Data Set Ready (DSR) | |
| System Ground (SG) | 5 | --- | 7 | System Ground (SG) | |
| Data Set Ready (DSR) | 6 | <-- | 20 | Data Terminal Ready (DTR) | |
| Clear To Send (CTS) | 8 | <-- | 4 | Request To Send (RTS) |
