Guralp Systems CMG-SAM - Manual (Page 19)

Operator’s Guide CMG SAM & CMG CRM
3. DIGITAL I/O INTERFACE
The primary digital interface for the systems is the multiple serial port card. Each card
can contain 1 or 2 dual UARTs (Universal Asynchronous Receiver Transmitters) and
upto 2 cards can be fitted to a SAM/CRM unit. This allows a system with upto 8 serial
ports to be configured.
The multiple serial port card is usually configured as several data inputs for a SAM unit
allowing it to collect data from upto 8 digitiser units located locally, using RS232 or
RS422 links, or more remotely using radio links or telephone modems.
Each of the serial ports on a module can be configured for a wide range of standard
baud rates (with different settings available for transmit and receive channels), allowing
a wide range of data links to be used depending on the required data rates.
Each dual UART is optically isolated to avoid ground loops which could degrade the
performance of the ADC’s.
The serial port module includes 32k RAM for data buffering and formatting by the
transmission/reception process.
Issue D March 2001 17