For the telnet, first check and make sure the IP address is still set properly in the unit. This will be under system config, then Ethernet port. If the proper information is still in there then try to ping the Atlas and see if you get responses. When you say it randomly won't allow calls, is it allowing some calls and not others or are no calls going through now? Under System config go to event logging and set ISDN L2 Formatted to Info and try a call. Copy and paste the results into a file and attach it to your reply, please. I'd like to see if we see any errors that indicate a change on the BRI lines that could be causing problems.