The Diamond Systems EMM-XT is a PC/104 serial communication module that delivers four independent, configurable RS-232/RS-422/RS-485 ports for industrial embedded systems. Built on the 16C554 quad UART architecture, each port features a 16-byte FIFO buffer for reliable data handling at speeds up to 115.2 kbps (expandable to 460.8 kbps with optional 7.3728 MHz crystal). The module supports jumper-selectable protocol configuration and 120Ω termination resistors for balanced serial modes, making it ideal for legacy and modern mixed-protocol deployments in compact form factors.
## Technical Specifications
• **Form Factor:** PC/104 standard
• **Serial Ports:** 4 independent ports
• **UART IC:** 16C554 quad UART
• **FIFO Buffers:** 16-byte transmit and receive per port
• **Data Rates:** 115.2 kbps standard; up to 460.8 kbps with optional 7.3728 MHz crystal
• **Protocols:** RS-232, RS-422, RS-485
• **Power Supply:** +5V DC
• **Operating Temperature:** −40°C to +85°C
## Key Features
• Jumper-selectable protocol configuration per port
• Jumper-selectable 120Ω termination resistors for RS-422/485 modes
• Selectable interrupt levels (2, 3, 4, 5, 6, 7, 10, 11, 12, 15) with full interrupt sharing and status register
• Eight programmable I/O address combinations via jumpers; custom OEM configurations available
• Serial ports on standard I/O headers; optional C-DB9M-2 cable provides dual-row 20-pin connector to two 9-pin male D-sub connectors
• Certain variants include 1-Wire interface module supporting up to 100 devices over 2000 feet
## Compatibility & Integration
• PC/104 (ISA) bus systems
• Windows and Linux drivers with serial port configuration utilities
• Port configurations vary by version: all four ports independently configurable, or two fixed RS-232 with two configurable for mixed protocols
