Unblocking a Blocked phone number

Would someone please tell me what I would need to set my computer up to access the Asterisk server in order to identify a caller’s phone number?

This caller continuously calls my cell number all hours of the night. When the call comes through to my cell number, the caller blocks their number and all I see are the words ‘number withheld’.

I understand Asterisk can unblock a blocked phone number and provide other identification information about the caller.

I need to know if I can use a regular land line phone to unblock blocked phone numbers as well. This harassment has happened on my land line phone as well.


Asterisk can not unblock a phone number. If the number is blocked it is not being sent.

Contact your cell phone company and telco about adding a service to not accept blocked numbers…

The solution is for you to purchase a DID 800 number from a provider that supplies the ANI/caller ID (for instance Vitelity.net among many others). Set this number up on your asterisk box as a trunk, and make an inbound route. Set the inbound route to call your cell phone back - the call will come in as the unblocked caller ID.

Find out how to forward your phone for busy/no answer, then program your new toll free number into it.
When a call comes in blocked, do what you have to do to not accept the call (iphone press the sleep/wake button twice really quick) then let the # fwd to your asterisk machine. Setup a rule to ring your cell phone again for the incoming call. IF the incoming call is “unknown” meaning the telco did not provide any number at all, the caller ID you eventually will get your own cell phone number. But if it is blocked/private, this will unmask it. It may be a good idea to set the type of call forwarding to only when you want, so you don’t get in any sort of loops. I for one use an iphone and a sip client on the iphone, so when the phone comes back to the iphone, it isn’t being sent to the ATT number, but being sent to the iphone sip client, with the unblocked caller ID of the person who originally called me, if I don’t answer in 20 secs, it will fail over to a vm box on my asterisk server.

Its my understanding Asserted ID / ANI is a simple bit activated. All the Caller id info is included in every call received even when blocked or private. This is so billing systems can still properly account for the caller location…or if the call receiver is a 911 / 800 service. The system is either honoring the privacy bit or isn’t. In the old days we would forward the call to an 800 number as it didn’t honor the privacy bit and the number was unmasked. This still works today.

So in modern systems is this privacy bit being handled on the receiving PBX?
In old Asterisk i thought i remembered a time when it didn’t honor the privacy bit and all calls were unmasked…years and years ago.

We have 800 numbers. I could care less about following “standards” or legality. I’m just interested in the underlining operations of ANI privacy bits and how or where in Asterisk the code accepts or denies such privacy bits.

To test the ANI number you are using dial 800-444-4444
Some CPNs are displayed different then the ANI

Privacy should be handled by the part of the network that is trusted to see the number. Some providers may be buggy and leak the information, but that would be a serious preach of privacy and possibly even illegal.

However, I believe that the USA does or did take the position with 800 numbers that, as the callee was paying, they should be allowed to know who would have been billed (ANI, not CLID) if the caller had paid.

This is the wrong forum for such questions.

Why respond if you have zero info? What is the correct forum to learn where in Asterisk ANI privacy bits are read?

I was responding to point out that you were probably wasting your time. I added a contradication of the assumption that a system that was not considered to be run by a network operator should expect to receive private information. In many cases, I actually forget to warn about the wrong forum, and add a note as a subsequent edit, although, in this case, I think I added it whilst reviewing the reply, before sending.

The correct forum for your original question was Asterisk Support. However, your revised question is not covered by any of the forums on this board, as it is a developer question. There is a sticky posting on Asterisk Support, telling you where to go for developer questions.

All the information available to end users will be in the various variants of ${CALLERID(…)}. As I rememer it, presentation not allowed is not implemented until the outbound leg of the call, and can be overridden. However, I would expect any responsible network operator to send a dummy value along with the presentation not allowed status, when sending to a non-network operator.

I’d also add that there are debugging options that will show you exactly what is being received in the signalling messages. I’m only familiar with the SIP ones, but there have been several examples, on these forums, of ones for PRI dahdi channels.