Trouble setting up two 1625 phones to use Direct IP or Intercom


I am having trouble setting up two 1625 phones to Direct IP or Intercom while still blocking ghost calls.

I have the Softkey setup to make a direct ip call to the second phone. However when I also enable “Check SIP User ID for Incoming INVITE” my direct ip call returns an error “486 busy”.

Is there something else I need to configure to get this to work or are these two settings not compatible?

Would using the intercom function instead of direct ip call work? I have tried to find info on how to setup the intercom, but the manual doesn’t quite help me out here. It says to specify The Intercom ID I want to call, however where do I set the Intercom ID of the phone?

Any help is greatly appreciated. Thank you.


The settings are not really compatible.

SIP scanners/hackers/scammers or whatever you want to call them use direct IP to send INVITES in the hopes of getting a response whereupon they will know that a device is reachable and then will attack it relentlessly thereafter.

The settings to prevent this use various methods to validate that the call is legitimate, but direct SIP cannot use these as it only requires 109@, for example, to be a valid direct IP call. The other methods are attuned to allowing messaging from SIP servers and proxies that can then filter out the direct SIP calls by looking at the IP and/or the SIP messaging.

Intercom usage is more complicated and requires additional messaging which is really not a function of direct IP.

As I assume the phones are remote to one another, your best bet is to use your firewall to filter what is an allowed IP at each site so that it will allow the remote phone to access your site and drop all others and vice versa when you call the remote site. You can then eliminate the “check SIP…” setting as the firewall is acting as the filter.


Maybe proxy only will work ?
Instead of SIP user ID.
By default SIp server should contain Other phone IP.


Thank you both for your replies. I have quite limited knowledge about VoIP and SIP, as this is my first set of VoIP phones. I have tried with the option Marcin mentioned, this however blocks my direct ip calls from the other phone.

Perhaps I should clarify my setup and what I am trying to achieve.

I have two phones on the local network. and 198.
These two phones have two active SIP accounts.
I need these two phones to be able to call one another internally/directly.
And I also want to be able to block ghost calls.

This is my problem for which I need a solution.

Is this possible with the 1625 phones, or do I need a different model?
If this phone model is capable, what must I do to get it to work?


What you mean by ACTIVE ? If this is registered then you must USE 2 account for IP calling (with ports). My option require that in SIP address is added 2 phone. I can test if this not work for you.
Your problem is that IP and ghost are same, it is packet on IP:PORT from unknown source.


What I meant be active, is that the two phones are both using 2 sip accounts (Private Tel Nr & Work Tel Nr)
They are both registered (I suppose) as they show me YES on green background.
I can make outgoing calls / and receive incoming correctly with both phone numbers.

I think I understand you correctly that the Direct IP call and a ghost call are they same type of call, as the ghost calls comes through the router connecting to my phone over the LAN using it’s IP address and port, just like the Direct IP call from the Phone#2 (which is

What do you mean with “If this is registered then you must USE 2 account for IP calling”?

Thank you.

These are the screenshots of the configuration:


With this you cannot prevent ghost call and have IP calls.
It is simply not possible as phone cannot see difference between IP call and ghost call.

Maybe, just maybe MULTICAST can work with phone preventing ghost calls but that is only 1 way audio.

For this to work you will need phone with more account and 1 account is used only for IP call.


Something else must be at play.

If the desire is to simply use two phones that are connected to the same LAN segment so that direct IP calling can be used, then how are ghost calls a factor? I assume the router is not open or forwarded for such, so how is anyone else able to penetrate into the network to reach a phone?


It can be port scanner or similar anything. Some programs or server make network topology.
What i do not get why they use IP calls when they have normal accounts (that part is strange).


I missed the part about his other numbers using outside services…so yes…scanners,etc.