We've got a MICS 4.1 system here with 2 PRI lines and we're having problems with conferencing external lines. The person on this end can hear both external parties fine and both external parties can hear the person hosting the conference call but the two external parties have trouble hearing each other - the volume is very low. We've tried playing around with system volume, etc but no luck. Any ideas? thanks.

The quick fix is to reboot the system. The problem is in that SW release, which would mean an upgrade

I might recommend a conference bridge if you are going to do a lot of calling.