A client would like to transfer calls while the outbound call is ringing.
They are able to transfer after the called party answers, but when they attempt while ringing the transfer fails.
Call Transfer Steps:
1) Inbound call answered
2) Flash hook then dial outside line
3) Flash hook to conference inbound and outbound calls
a) Only works if called party answers
b) If flash hook while ringing the outbound call drops
Atran IAD settings (TA900e):
voice transfer blind
voice feature-mode network
voice flashhook threshold 300 1000
no voice number-complete disable star
no voice number-complete disable pound
voice timeouts connected 12
voice timeouts connecting 5
voice timeouts alerting 5
voice timeouts delay-refer 250
voice timeouts preconnected 5
voice timeouts preconnecting 5
voice timeouts emergency-callback 0
voice hold-reminder 10 30
voice park-return 60
voice flashhook mode interpreted
voice transfer-mode local
voice forward-mode network
voice call-appearance-mode multiple
voice modem-passthrough-mode both
voice transfer-on-hangup
voice conferencing-mode local
voice conference local originator onhook persist
voice conference local originator flashhook drop
voice conference local party-disconnect continue
voice conference local max-sessions 3
voice disconnect-mode dialtone
voice codec-priority trunk
voice num-rings 0
FYI - voice transfer unattended was tried as well and did not resolve.
The call maybe failing on the provider side have you called them to see if they are getting the call and if it is being blocked by them and find out why. Because of the high amount of toll fraud many providers are blocking calls that the from number in the from message doesn't match a number on their system. Sometimes you may have to perform some Header Manipulation Rules to add or modify fields they need for additional matching so they can verify it's a legitimate call.
John Wale