*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)  

To understand which HF digital mode can be used to transfer binary files, let's analyze each option:

### Correct Answer: PACTOR
- **Why PACTOR is correct:**
  - PACTOR is a digital mode specifically designed for efficient data transfer, including binary files. It uses error correction and can operate over noisy channels, making it suitable for sending files reliably.

### Why the Other Choices are Incorrect:
- **A: PSK31**
  - PSK31 is primarily designed for keyboard-to-keyboard text communication. It is not optimized for transferring binary files, as it focuses on real-time text exchange.

- **C: RTTY**
  - RTTY (Radio Teletype) is a mode that transmits text using frequency shift keying (FSK). While it can send text messages, it is not designed for binary file transfers and lacks the necessary error correction features.

- **D: AMTOR**
  - AMTOR (Amateur Teleprinting Over Radio) is a mode that combines aspects of RTTY and error correction. However, it is mainly used for text communication and is not suitable for transferring binary files like PACTOR.

### Summary
- **Key Takeaway:**
  - PACTOR is the only mode among the options that is specifically designed for transferring binary files, making it the correct choice.

### Useful Rule of Thumb:
- When choosing a digital mode for file transfer, look for features like:
  - Error correction
  - Efficiency in data handling
  - Capability to handle binary data

This will help you identify the most suitable mode for your needs.