Solved BT HSIPT - Forward to Mobile (CLIP)

[TBUMike]

Hi All.

I'm hoping someone can help.
We're in the process of migrating our SIP trunks from Gamma to BT (BTHISPT).
I Have a guide from BT - and also gone through the 3cx Guide... But i'm hitting a brick wall without Diverts.
I'm Told by BT that it supports CLIP - and that our 3cx Server is Misconfigured.
They do not support "3rd party hardware" - So other than emailing me the same guide again, they will not support 3cx.

Following both guides - We Cannot get Calls to work, if our office Mobile (a UK Number) is part of the queue (for our out-of hours service).
This is because in the BT Guide - and the 3cx Guide it states on the outbound parameter to set FROM: User-part to "Originator Caller ID".
If this is done, we get a BT woman say "I'm sorry, your call cannot be completed at this time, Please try again later, then terminates the call" - Even though we also have 3cx Clients in that Queue.
If i change this to "Caller Num" - It works, But reports our Main trunk DDI as the Caller ID - Not the original caller ID.
I have Tried setting the Caller ID to Convert inbound Caller ID to E134 format - But just cannot get 3cx to forward calls to a mobile / cell without reporting one of our Trunk numbers.

Has Anyone Actually Ever got this to work? I have set up Many Many providers on 3cx Before, and never had something as needlessly difficult as trying to get BT Sip Trunking working!

The way our Process is setup is Incoming calls to :
During Office Hours:
BTHSIPT - Call Queue (8500) - All SIP Handsets
Out of Office Hours
BTHSIPT - Call Queue (8501) - 1 On Call Agent (SIP Handset) - 1 Mobile Extension (dummy extension, permanently forwarding to Mobile Number).

The Outgoing call to the mobile number, is killing the whole system if We present Originating caller ID.
The only thing showing up in the Logs is after the BT Voice answers is a BYE:

06/04/2023 19:26:49 - L:1690.2[Line:10001>>07<our On call mobile>] got Terminated Send Req BYE from 217.32.186.185:5060 tid=b87778674255c55f Call-ID=oTtjZONn4DFPME5dvgiQFw..:
BYE sip:SD9ui30-vp9pm63261dnpvornivdcu7srhvhgddasop5dbj9vutfc5aef3v1000030@217.32.186.185:5060;transport=udp SIP/2.0
Via: SIP/2.0/ ;branch=z9hG4bK-524287-1---b87778674255c55f;rport
Max-Forwards: 70
Contact: <sip:44< our sip DDI>@<our 3cx Server IP>:5060>
To: <sip:07<our on call Mobile>@<our domain>.co.uk>;tag=SDpi7pf99-1340160263-1680805597966
From: ":On Call"<sip:+44<Originating Caller ID>@<our domain>.co.uk>;tag=bee4a02b
Call-ID: oTtjZONn4DFPME5dvgiQFw..
CSeq: 3 BYE
User-Agent: 3CXPhoneSystem 18.0.7.312 (312)
Content-Length: 0

However - If we change it to Present Caller Num in Outbound - It displays the Trunk DDI in the caller id on the Cell.

Am I Missing something simply stupid?

Thanks in Advance

 

[YiannisH_3CX]

Hi @TBUMike

Have you asked BT to enable Class 5 CLI on their end?

 

[TBUMike]

Hi Yiannis - It was in the build instructions for the SIP Service - and when queried all I get is "we dont support 3rd party hardware - refer to your manual or Hardware vendor" - Although it took them 4 days to figure out that my SIP authentication credentials were wrong, lol..... I have emailed them Specifically asking to check that CLI Type 5, CLIP is enabled on the Service, just in case

I See where you are going with this - It does appear their service is accepting the Calls - then routing them to a vocal error due to CLID rather than Returning an Error in the SIP Headers.

I was just wondering if I had missed something simple, that everyone with Experience on BT knows that I Have Missed!

 

[leejor]

Has BT verified that it will allow you to spoof the caller ID (CLIP no Screening), which is essentially what you are attempting to do. Many providers only allow caller ID numbers, to be sent, that have been assigned by them, blocking anything that they see as invalid, which would seem to be the case, at present. The only other issue might be that the caller ID is in an incorrect format.

The fact that they keep repeating that they do not support third party hardware, makes me think that this may not work the way you hope it will.

 

[TBUMike]

I really hope that's not the case. As I explained our current setup - and stressed that the ability to present the originating caller ID on forwards from a queue to cell was a mission critical deal breaker. BT Sales assured me it is capable of this.. And Thier own 3cx guide states to set originating caller id as the from header.. I will double check this with them though. Thanks for the suggestion.

 

[leejor]

I learned long ago to take what sales people tell me, with a grain of salt. Usually once the "contract is signed", it's the support people that have to deal with the aftermath, when things don't work quite the way it was promised. Obviously not the case every time, but...

That said, i would go back to BT and see if there is someone that can give you a definitive yes or no, as to whether or not this will work. Probably someone with a technical background. There may, as suggested earlier, be an option that is required to be enabled. Perhaps someone at BT could analyze a failed (rejected) call, to see what they don't like.

 

[TBUMike]

Yeah, it's a valid point - I have emailed them to get a definitive answer - Hopefully I get a useful response!

 

[YiannisH_3CX]

Please confirm with BT that the Class 5 CLI service is enabled and let me know what they say. If you are still having issues we can take a look at it. I would love to confirm it on our test trunks but Class 5 CLI is disabled on our trunks as well.
If I remember correctly Class 5 is disabled by default.

 

[darnell]

Hi @TBUMike

Did you manage to get this resolved?

We're having the same issue with a BT SIP Trunk where we cannot spoof the caller ID, we 100% have Class 5 CLI enabled on the trunk but as soon as I specify any other caller ID other than the trunk number I get the BT we're sorry message.

I have an ticket open with DWP who we purchase the trunks through so will let you know if they're able to shed any light on it.

 

[TBUMike]

Hi @TBUMike

Did you manage to get this resolved?

We're having the same issue with a BT SIP Trunk where we cannot spoof the caller ID, we 100% have Class 5 CLI enabled on the trunk but as soon as I specify any other caller ID other than the trunk number I get the BT we're sorry message.

I have an ticket open with DWP who we purchase the trunks through so will let you know if they're able to shed any light on it.

@darnell - Not Yet.. After Speaking to BT there is an issue with the build (i have edited this reponse as i've just had a further update from them)... So they Ordered what they call "Smart Divert" - Which has a seperate component under it which is called Number Presentation - That has not been built to our trunk, despite being ordered.. So we have "Smart divert" - But No CLIP currently enabled. This is why the half baked previous response was "it's your server" because support could see the smart divert product, but didn't bother checking if CLIP (or number presentation) was enabled. - They are apparently chasing this down for me now..... Will update if / when they fix it. Good luck with your Issue.

 

[darnell]

I got the following response from BT but I don't understand what they mean by PPID & PAID, can someone advice what my P-Asserted should be?

From: +441200423*** - this must be the number you want to present in +44 format

P-Preferred: 441200871*** - this must be the trunk DN in 44 format and sent as PPID, not as PAID

--

This is what the PCAP shows at present for reference

What the PCAP shows:
FROM: 441200423*** (must be +44 format)
PAID: 441200871*** (header incorrect, must be PPID and not PAID)

I changed the format of the number I was spoofing to +44 instead of 44 but its the changing from PAID to PPID I don't understand.

I've attached my outbound settings for reference.

 

[darnell]

I've got it working!

I changed P-Preferred Identity : Display Name - "OutboundLineId" Outbound Line Caller ID taken from Outbound caller ID Settings
P-Preferred Identity : User Part - "OutboundLineId" Outbound Line Caller ID taken from Outbound caller ID Settings
P-Preferred Identity : Host Part - "GWHostPort" gateway/provider host/port

That seems to allow me to spoof a number now, I tested a few things and everything else seems to be working as it should.

 

[leejor]

The time and trouble that you've had to go through to get this working , is no doubt, going to be a big help, to others, that will have the same issue, with BT, in the future.

 

[YiannisH_3CX]

Glad to see you were able to got this working and thank you for sharing your solution. We will contact BT to see if they changed something from their end and make any necessary changes to our guide and template.

 

[TBUMike]

I've got it working!

I changed P-Preferred Identity : Display Name - "OutboundLineId" Outbound Line Caller ID taken from Outbound caller ID Settings
P-Preferred Identity : User Part - "OutboundLineId" Outbound Line Caller ID taken from Outbound caller ID Settings
P-Preferred Identity : Host Part - "GWHostPort" gateway/provider host/port

That seems to allow me to spoof a number now, I tested a few things and everything else seems to be working as it should.

Hi Darnell - They're still working on actually building my trunk with a CLIP enabled - So unable to test.. But i'm glad you have yours working, and thank you for providing a solution for a problem that I may likely hit soon!

 

[TBUMike]

As an update - I am still getting the same issue - I did try your settings Darnell and it hasn't changed the outcome.
Back to BT support i go!

 

[TBUMike]

Hmm - Plot thickens - Now i appear to be getting an error - 401 Unauthorized when i trace the failing diverts.... so they changed something! - at least it gives me an error now!

 

[Billy Wright]

Hi i am having the same issue after porting to BTW, the divert to mobile only displays the main trunk number, also when you dial international or a none geo number it displays the main trunk number to 07, 01, 02 , 03 numbers it displays what you have in your extension settings, no one at BTW as a clue to be honest.

 

[leejor]

If the extension setting number is being displayed on some calls, then it is obviously being sent on all calls, I have to assume. It would seem to be a BT (software) decision as to which number is passed on to the called party, or, onto the carrier they connect to.

 

[TBUMike]

Really late update on this - Apologies it was so long.
Our SIP was not built correctly by BT. They eventually added what they call number presentation (basically CLIP) to our build - and magically it started working! - issue is now resolved

This was ordered when I signed the contract, however they requested "Smart divert" from the build team, and not Number Presentation... Took several layers of technical support before someone twigged that! - Got there in the end though.