The mobile softphone clients are obnoxious to set up, but once setup have less points of failure in the talk path for the phones. Probably not worth it if you got the other issues working.Turned out the issue was RTP being set to RFC 2833 instead of inband on the phone switch.. So that not only fixed the users dialing 911, it also eliminated a long standing hard to replicate complaint of DTMF issues when dialing into Exchange UM and entering voicemail PIN's.
Asked my basement phone troll about the Avaya-X lite client for IOS, and he claims that it doesn't do anything EC500 doesn't do, and would lock up the helpdesk with support requests as the phone config is extensive. Is he bullshitting me?
What did you have for an SBC again?