OpenR2 is a library that implements the MFC/R2 telephony signaling protocol over E1 lines.

As of Asterisk 1.6.2 support is already merged in the official source and patching is NOT needed. No more patches for 1.6.x will be provided, use 1.6.2.

For Asterisk 1.4 the latest patch in downloads is the only one supported, old patches are unsupported.

Asterisk 1.2 has patches available but is deprecated and unsupported.

FreeSWITCH has full support with openr2 trunk and FreeSWITCH/FreeTDM trunk. See http://wiki.freeswitch.org/wiki/FreeTDM_OpenR2

OpenR2 with Asterisk Mailing list: http://lists.digium.com/pipermail/asterisk-r2/

Official Web Page: http://www.libopenr2.org/

Downloads Web Page: http://code.google.com/p/openr2/