SCM TTL to RS485 Module, 485 to Serial UART

Automatic bi-directional transmission control
Uses differential signaling for noise immunity
Distances up to 1200 meters
Speeds up to 2.5Mbit/Sec
Multi-drop supports up to 32 devices on same bus
Built-in poly fuses for over-current protection
Built-in transient surge protection diodes for over-voltage protection
Transmit and receive indicator LEDs
Comes with connectors and headers for easy hookup
3.3V & 5V operation