Call rebound does not and has not worked since it was launched a version or two ago. It seems to be a coding error, hopefully it can be fixed in a service pack update or version 13. What happens when you click the radio button to send the call to an external number and click the "Rebound" checkbox is that the message saying "Caller from xxx-xxx-xxxx phone number, would you like to accept or send to voicemail" starts as soon as the call is forwarded, not when you answer the call. So if I get a call on my cell forwarded from the 3cx system and answer it the second it comes in, it is six digits into telling me what number is calling, so I get "xxxx (last 4 of the number) phone number, would you like to accept or send to voicemail". If I wait a few rings to answer the call, I can't even here the number, and I only get part of the message about taking the call or sending to voice mail.