Hi Matthew, unfortunately fixing the channel definition does not help. As soon as I turn on ss7 in zapata.conf the error message is shown. I have tested different asterisk version, and I have found out that there is a version dependence. The error message does not appear with asterisk SVN-trunk-r117431, but with SVN-trunk-r118178 and also when using asterisk-1.6.0 branch. Regards, Andreas