Fax - different length extension

Discussion in '3CX Phone System - General' started by DeepB, Jan 11, 2018.

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  1. DeepB

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    Hello,

    we have a head number with a lot of extensions

    Side question: we do not buy DIDs, everything that is called after our head number is just forwarded. I now used DIDs for that, and it seems to work, is that correct?
    For instance our head number is 0043 12345. And if someone calls 0043 12345 678 it calls to the extension 678. If someone calls 0043 12345 98725 it calls to the extension 98725. No need to add DID at provider, and in former PBXs I only had to add the extension.

    Back to the main question:
    We have 3 digit extensions. With one notable exception. Our Fax line has the extension 30. Our User Fax extension has 4 digits.

    So we have for instance:
    30 - Fax
    100 - User 1
    7100 - Fax User 1
    315 - User 2
    7315 - Fax User 2

    In our former PBX System (Askozia, bought by 3CX, that is why I am here now) I could just detect an incoming fax, no matter the called number and have it forwarded to an email address. Is that possible in 3CX?

    As this has been like that for 20 years (and was handled well by all our former PBX-Systems!) I cannot just change the Fax number.

    Any suggestion on how to proceed?

    thank you
    Daniel
     
  2. sip.bg

    sip.bg Active Member

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    With 3CX you can't detect incoming fax, all extensions must be the same length, incl. system ones, e.g. 3 digits. You need to set DID numbers into SIP trunk provider settings and set destinations for them into inbound rules. It is different from Askozia / Asterisk.

    For regular extensions you can assign SIP IDs, which could be of different length.
    DID numbers can be with different length, but minimum 4 digits.
     
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  3. DeepB

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    I am not sure I understood your post correctly, but my understanding is no -30 fax possible at all?

    Any workaround ideas? Doing some number mixing magic on the beronet (ISDN<->IP box)?
    That is something that will be a very hard sell internally.
     
  4. sip.bg

    sip.bg Active Member

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    If you have 3-digits extensions in your 3CX, the fax extension must be also 3-digit, e.g. 300 or 030.
    You can't have extensions like:
    30 - Fax
    100 - User 1
    7100 - Fax User 1
    315 - User 2
    7315 - Fax User 2
    This is possible in Asterisk-based PBXs.

    However with SIP ID, you can dial 5100 for extension 100, or even this SIP ID can be alphanumeric, e.g. user1

    You need to define DID numbers like (without spaces):
    0043 12345
    0043 12345 678
    0043 12345 98725


    Then you can point these numbers to different extensions.
    Please note you can not change extension number length in 3CX, once installed.
     
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  5. DeepB

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    Ok, so if I understand correctly I can have the external DID 0043 12345 30 mapped to the internal extension 888. Is that correct so far?

    What would the correct DID-format be?
    right now I have *110, *130, and *678. Can i Mix-and-Match for instance *110 and 0043 12345 30?

    thanks
    Daniel
     
  6. sip.bg

    sip.bg Active Member

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    Yes, you should be able, depends what your provider is sending. If no result, you can check into activity log or capture the traffic.
    Regards.
     
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  7. lneblett

    lneblett Well-Known Member

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    Not sure I understand,- you stated - "we do not buy DIDs" and in the same sentence you indicated - "I now used DIDs for that". The bottom line is that 3CX sees and Inbound INVITE and looks at the headers to see what information is contained in them. It then looks at what headers you selected to be of interest and compares that the rules you created so that it can route the call accordingly.

    All extension within 3CX must be of the same length, but you can use a SIP ID withing the extension settings to make it such that a call can be accommodated using the extension number or SIP ID. For instance, your main operator extension might be 100, 1000, or 10000 (3, 4 or 5 digits), but you can put "0" in the SIP ID field for one of the aforementioned and internal extensions can then reach the operator/receptionist by only dialing 0.

    The "*" is a wildcard. So, if you have an inbound DID of 123456789, the rule might read send call 123456789 to extension 200 or, if *23456789, or *3456789 or even *9 could be used to direct the calls to extension 200, just so long as no other DID (34567889, 11111119, 229, etc.) also match *9 (in this case) to the rule.

    So, in your example *110 does not match any string from within your DID of 0043 12345 30.
     
  8. DeepB

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    Is there any way to check what the header of an incoming call is?

    To stick to my examples, I tried to add the following DIDs:
    00431234530 - did not work
    *430 - also did not work.

    EDIT: I call 0043 12345 30, and should reach the fax

    EDIT2: when capturing the traffic I get that:
    Code:
    Via: SIP/2.0/UDP 192.168.40.100:5060;branch=z9hG4bK-524287-1---d1a1237ba6a11406;rport
    Max-Forwards: 70
    To: <sip:100@192.168.40.100>
    From: "0676MYPHONENUMBER"<sip:00676MYPHONENUMBER@192.168.40.100:5060;nf=e>;tag=f08ec977
    Call-ID: WgfHYtwLaLZ3jeBvkNThmQ..
    CSeq: 1 CANCEL
    User-Agent: 3CXPhoneSystem 15.5.6354.2 (6354)
    Reason: Q.850;cause=16;text="Normal call clearing"
    Content-Length: 0
    Is that the correct line?
     
    #8 DeepB, Jan 11, 2018
    Last edited: Jan 11, 2018
  9. sip.bg

    sip.bg Active Member

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    I can't see the called number in the log above, probably extension 100 is your operator and DID not found exception routed the call to operator.
    If logging is not set to verbose, set it and replicate the call.
     
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  10. DeepB

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    Now I get the following:

    Code:
    Via: SIP/2.0/UDP 192.168.40.4;rport;branch=z9hG4bK1Zj2ea818Zc9S
    Max-Forwards: 70
    From: "0676MYNUNMBER" <sip:10000@192.168.40.100>;tag=HSaUND6H278Bg
    To: <sip:30@192.168.40.100>
    Call-ID: e91c79b1-1718-1233-c895-3bb152f7bb79
    CSeq: 70313518 INVITE
    Contact: <sip:10000@192.168.40.4:5060>
    User-Agent: Berofix VOIP Gateway (3.0.04)
    Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, PRACK, MESSAGE, SUBSCRIBE, NOTIFY, REFER, UPDATE, INFO, REGISTER
    Supported: timer, 100rel, replaces
    Privacy: none
    Content-Type: application/sdp
    Content-Disposition: session
    Content-Length: 219
    P-Asserted-Identity: <sip:0676MYNUNMBER@192.168.40.4;user=phone>
    P-Preferred-Identity: <sip:0676MYNUNMBER@192.168.40.4;user=phone>
    Remote-Party-ID: <sip:0676MYNUNMBER@192.168.40.4;user=phone>;party=calling;privacy=off;screen=no
    
     
  11. sip.bg

    sip.bg Active Member

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    It is external gateway (Beronet?) who is handling the DID number, it is not reaching the PBX -- the incoming call is for extension 30 (or not part of the above log):
    To: <sip:30@192.168.40.100>
    This means you need to adjust handling of DID numbers in Beronet configuration, so to send call to ext. 888 or other fax extension in 3CX.
    Switch off verbose mode logging, when done.
     
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    #11 sip.bg, Jan 12, 2018
    Last edited: Jan 12, 2018
  12. NickD_3CX

    NickD_3CX Support Team
    Staff Member 3CX Support

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    Expanding on what @sip.bg said, in the beronet dialplan reformat the destination number so that it is sent in at least a 6-digit format, so instead of your "To:" header being "30", it would be e.g. "000030". The reason is that DIDs can't be added for less than 4 digits, but its recommended to use at least 6.

    Then create DID based on the 6-digit format in 3CX and then point them to the destination you want.
     
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