I have been struggling with this for a while now, and I know it's been talked about before, but I feel like I've tried just about everything. Problem 1: When an incoming call is transferred to an external number, the callerID on the external phone shows our company's main number. We would like the original callerID to be transferred through. It's causing me a lot of headaches with our salesmen because they do not retain the potential customer's information. Problem 2: I believe I am struggling with the way I am asking questions to Time Warner because they have let me know on two separate occasions that this should work. I may also be misinterpreting the capabilities of 3CX. Question: Is it possible to send the original CallerID on a call transferred externally to a user's mobile phone? Note, I can forward it while the user is away using the 302 diversion header forwarded to their cell phone. I cannot figure out how to transfer it from one user to another. Question 2: When a call is transferred to an external number, will it always continue to tie up one of the trunk lines until that call is completed? Even if it's two external numbers speaking with each other? Or is there a way to essentially cut our PBX out of the call, so they connect together directly. Equipment: 3CX Phone System Professional Edition Version 14 Time Warner Cable SIP Trunk InnoMedia Gateway/Switch (Time Warner's) Secondary - Time Warner (3) Coax lines on Patton 4114 FXO gateway Polycom SP450 Phones What I've tried Extension Forwarding Rules I've recently learned that using the 302 diversion header does work for calls to the extension's unique DID. It forwards the call to the external mobile phone with the original CallerID. It does not tie up one of our lines. If I do not use the 302 Diversion header, the forwarded call shows our company main number and ties up one of our trunk lines. Transferred calls do not appear to be impacted by these settings. So calls transferred from our building to our sales team always look like they're coming from our main number. These calls will always tie up a trunk for the entirety of the call. Outbound Parameters on the SIP trunk--I've messed with a lot of them, but this is how I believe they are supposed to be setup. Thanks for taking the time to read through this!