There have been some problems with stds-754@xxxxxxxx with people getting automatically unsubscribed due to excessive mail hop counts... but perhaps they are fixed now. If you think you have been unsubscribed, go to http://listserv.ieee.org/cgi-bin/wa?REPORT&z=3 and resubscribe. There is no harm if you weren't really unsubscribed. stds-754@xxxxxxxxxxx has been shut down, so don't use that any more.