In order to "hear" your button press, the OBi would have to answer the incoming line, before ringing your phone. That has several undesirable properties: If the caller hangs up before you answer, he would still be charged one minute for the call (possibly a lot, if calling from overseas). If your service, e.g. Google Voice is set to ring other phones in addition to the OBi, you wouldn't be able to answer from the other phones, because OBi would have seized the call. Call logs would incorrectly show calls as having been answered.