Emerald-MM-8PL offers 8 multi-protocol serial ports on a single PC/104 module with complete software configurability via the operating system. Each port can be individually selected for RS-232, RS-422, or RS-485 under software control. Both local-echo and non-local-echo modes are supported for RS-485. I/O addresses and interrupt levels are also programmable, with interrupt sharing available for any number of ports. Each port may further be enabled or disabled in software. All configuration data is stored in an on-board EEPROM that is loaded automatically on power-up.

For applications where fixed addresses are desired, four groups of preset addresses are available with jumper settings that override the programmed settings. Line termination for RS-422/485 modes is also jumper-selectable.

Emerald-MM-8PL offers 8 convenient digital I/O lines. The direction of each line is independently
programmable. Diamonds Universal Driver software provides software support for these digital I/O lines.

Two I/O headers are provided, with four serial ports and four digital I/O lines on each header. The board operates on +5V only, eliminating the need for a +12V supply that is often required for serial port operation.

Emerald-MM-8PL is based on the industry-standard 16C654 quad serial port IC. Two ICs provide a total of 8 serial ports. Each port contains 64-byte transmit and receive FIFOs to support the high-speed 460.8kbps data rates. Drivers are available for a wide range of operating systems including Windows 10 and Linux.

Note to existing customers: Emerald-MM-8PL is a form-fit-function replacement for our previous product Emerald-MM-8P (EMM-8P-XT) with the single exception that the maximum RS-232 data rate is limited to 115.2Kbps vs. 460.8Kbps on EMM-8P-XT. This change is due to the end of life of the RS-232 transceiver used on EMM-8P-XT. Except for this component, all other components and the PCB are the same between the two boards.