atcomsystems.ca/forum Forums Telephony Discussion Phone & VoIP Systems Samsung Telephones & Systems 7400 issues

We have a networked 7400 that is experiencing phantom ringing and intermittent no audio issues on the PRI. These issues only seem to happen on incoming calls from the on-site PRI. Oddly enough, this site is also experiencing strange characters showing on the keysets and the time on the display will change for a few minutes then change back to the correct time. AT&T has done testing on the PRI and has not found any problems. I have replaced the cabinet, LP40, CRM, MP40, and PRI card. The phone system has been reprogrammed, upgraded to 4.75 and the media card has been replaced. The network is a VPN. We are out of ideas, any suggestions would be appreciated.

i'll pm you, we've experienced almost identical issues with networked 7400's

oh crap we're networking 4 7400's in June. Should I be concerned?
Thanks,
John

We have several 7400's networked with no issues. This is an isolated case. You should be fine.

No concerns it sounds more environmental than anything and it seemed too long and boring to post here but here's the jist. Being he swapped every part and the problem is new environment is really the only place to go next. We had an car dealership install an air compressor in the room adjacent to the phone room and every time it turned on it would cause a different problem with the system, similar to his issues. We ended up getting an earth ground to the system which made it better but shielding the pri cables to the NIU resolved the problem almost 100%. The crazy displays were resolved with ferrite cores (on the phones effected) and in extreme cases shielded cable to the end user, usually reserved for welding and cnc shops. Environment seems to come in to play way more often nowadays and I never would have believed it until it happened to us.