Ever since we upgraded from v3.2/IP406v2 to v9/IP500 our 5410's have had an issue with the speakerphones making a strange noise when calling internally. It starts out really soft after using the speakerphone for about a minute or two then gradually gets louder. The sound itself sounds almost like feedback. If the users hang up then redial it works fine. What could cause this? We didn't change out our digital station expansion modules because our VAR said they'd work fine moving from the IP406v2 to the IP500.
Thanks!
Thanks!