Rilawich Ango wrote: > My configuration is simple as below. > > SIP phone <-> asterisk <-> CISCO <-> T1 > > Do you mean the hum noise is created by electric-magnetic field? > Asterisk can do nothing to eliminate it? > That would be my bet. No, Asterisk can't do anything to remove EM noise. That's up to you since EM noise can just about always be filtered out. The most likely source is from telephone cables being run too close to power cables, fluorescent lights and so on. Improper shielding of components inside your PC could also be your problem.
If your connection to the outside world is T1, it's unlikely to be an external problem. (digital signals aren't affected in this manner by EM interference) It's possible the SIP phone itself is faulty - other than that, make sure your Asterisk box and Cisco gear aren't located right next to heavy duty power cables or transformers. _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
