Mismatched baud rate, data bits, or parity. Double-check device datasheet. Also try swapping RX/TX lines if using TTL.
| Feature | SSCOM 5131 Portable | PuTTY | Tera Term | RealTerm | |--------|----------------------|-------|-----------|----------| | Portable (no install) | Yes | Yes (but needs config files) | No | No | | English interface | Full | Full | Full | Full | | File send | Raw + Xmodem | X/Y/Zmodem | Full X/Y/Zmodem | Binary+ASCII | | HEX input/easy | Very easy | Clunky | Moderate | Advanced | | Timed multi-command | Yes (8 slots) | No | Script needed | Yes | | VT100 terminal | Yes | Yes | Yes | No | | Size on disk | <300 KB | ~500 KB | ~7 MB | ~1 MB | sscom 5131 english portable