The Titan Eclipse plug-ins offer a TTCN-3 IDE for the Titan Execution environment. TTCN-3 is a standardized, modular language specifically designed for testing. Eclipse Titan offers a free and open source (FOSS) compiler both for TTCN-3 and for ASN.1 (Abstract Syntax Notation One).
http://polarsys.org/sites/default/files/custom_uploads/TITAN%20Datasheet%20A4%202.1.pdf
listed on the titan.core page
#Compressed update site and SHA512 checksum for the Eclipse plug-ins: