DS-KD8003-IME1-(B), also having trouble with this one.
The camera is viewable, device is coming up as an intercom, but when attempting to call, I get the error "Call declined (480)".
having gone through every setting I could, I found nothing referring to auto answer or what I would think the problem would be, no luck.
Assuming this is firmware related, and I'm having the same problem as @Silvaskin cannot add "special firmware"
Currently sitting at a clients house realizing i shouldn't have sold the product assuming it would work, no response from Hikvision, or Chowmain on all possible addresses.