Guralp Systems CMG-DM24 - Manual (Page 24)

CMG-DM24
3.6 DM24 USB Host Operations
DM24 Mk3 USB host option
This interface enables the DM24 to record GCF data to a standard USB
disk drive or Flash memory stick using the ISO 9293 FAT filing
format – readable by Linux, DOS, Windows and Mac OS.
Equipment fitted with the USB Host Port connector (labelled
USB BOMS – Bulk Only Mass Storage) will automatically record the
current real time data to the USB device when it is plugged in.
To do this, the DM24 should be in DIRECT or DUPLICATE
transmission mode so that real time data is being fed to the standard
transmit buffer used for normal serial data transmission. The USB
process runs in parallel with the serial transmit thread using the data
in the transmit buffer. It does not matter whether the serial port is
connected or not.
Other transmission modes do not pass useful data via the serial port
and so cannot be used with USB devices. In particular FILING mode
saves all data to the internal flash memory (for later download via the
serial port or FireWire interface) and only outputs “heartbeat” status to
the serial port to inform systems monitoring the port that the unit is
present and operating. FIFO and ADAPTIVE modes use the internal
flash as an extension to the serial transmit buffer as explained in
24 Issue N