*Question E2E08:
Which of the following HF digital modes can be used to transfer binary files?*  

*Correct Answer is  B: PACTOR*  

### AI Response: (may contain errors)  

PACTOR is the correct answer for transferring binary files over HF digital modes. Here's why:

1. **Why PACTOR is Correct:**
   - **PACTOR** is specifically designed for reliable data transfer, including binary files, over HF radio. It uses error correction and automatic repeat requests (ARQ) to ensure data integrity, making it suitable for transferring complex data types like binary files.

2. **Why the Other Choices are Incorrect:**
   - **PSK31**: This mode is primarily used for real-time keyboard-to-keyboard communication. It is not optimized for binary file transfer due to its lack of robust error correction and lower data rates.
   - **RTTY (Radio Teletype)**: RTTY is an older mode that is mainly used for text communication. It does not have the necessary error correction features to reliably transfer binary files.
   - **AMTOR**: While AMTOR does include some error correction, it is primarily used for text and is not as efficient or reliable as PACTOR for binary file transfers.

3. **Useful Information:**
   - **Error Correction**: PACTOR's use of error correction and ARQ makes it more reliable for file transfers compared to modes like PSK31 and RTTY, which lack these features.
   - **Data Rate**: PACTOR can achieve higher data rates than the other modes listed, which is beneficial for transferring larger files.

In summary, PACTOR is the most suitable HF digital mode for transferring binary files due to its robust error correction and higher data rates.