Googling for a while has turned up evidence that this can be corrected by a carefully-crafted "dialplan" for the Sipuras, at least, but the avaialable documentation is, let's say, a little convoluted.
Try this on Sipura (*x.*x.)
Seemed to work for me. Cameron _______________________________________________ --Bandwidth and Colocation provided by Easynews.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users