# Earthworm Modules:
gcf2ew Overview

(Last Revised 17 May, 2006)

gcf2ew is a Guralp Digitizer GCF DM data feeding program for Earthworm. The gcf2ew module provides for three modes of data input:

- Lantronix MSS100 serial to IP server
- Direct Serial connection to a DM
- Network connection to gcfserv

This version uses a Lantronix MSS100 for the reliable transmission of data over a network. It also provides the capability for direct serial connection to a DM24 digitizer from a Solaris workstation. The direct serial connection makes full use of the BRP protocol that DM24's use to correct for serial line errors. In addtion, the gcfserv program can be used to serve data to multiple receivers using a PULL protocol that the gcf2ew module is configured for. V1.0.0 and later has SCNL capability for EW v7.0 and greater. It needs to be compiled with EW v7.0 and later, but is backward compatible to earlier versions of Earthworm.

When running with an MSS100 or gcfserv, the module provides a reliable reconnection if the IP connection should drop. The network input also uses the Guralp BRP serial protocol to rewind the DM to request missing packets.

Module Index | gcf2ew Commands