Our system is able to forward to your internal extension (PBX Connect feature) as long as you have an auto attendant. In other words, if a live operator answers the phone before transferring them to your internal extensions, the system won't be able to forward to your extensions/desks automatically. Please note, once Grasshopper has successfully forwarded to an unavailable internal PBX extension, its voicemail will take the message and not Grasshopper. In order for Grasshopper to take your messages, you'll need to use the Call Announce or Call Screening settings and not PBX Connect. However, this requires you to have an operator that answers calls before transferring them to your internal extensions. If the operator knows you're not available, the announcement can be ignored, letting the call to go to your extensions voicemail on your Grasshopper account. If the operator knows you're available to take the call, the call can then be transferred to your desk.