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  • 1.  Format for telephone numbers

    TM Forum Member
    Posted Mar 27, 2023 09:04

    Is there any definition for the format used to represent telephone numbers? Or is it only a string?

    We are using a RegEx that restricts the value to the pattern

    +<cc>-<ndc>-<sn>[[-]<ddi>] 

    with

    <cc> ... country code
    <ndc> ... national destination code
    <sn> ... subscriber number
    <ddi> ... direct dial in
    [...] ... denoting optional parts

    as defined e.g. in  ITU E.123, E.164 and also aligned with RFC3966.

    Our problem:

    We also need to express number ranges of two different types:

    •  "decades", i.e. numbers with the last digit taking any digit, e.g. with wildcards:
      "+49-228-181-31?" meaning any possible one-digit extension allowed
      "+49-228-181-31??" meaning any possible two-digit extension allowed
      ...
      "+49-228-181-31*" meaning any possible extension allowed
    • real ranges, e.g. "+49-228-181-31(00-99)"

    Is there any defined format to express the above range types?

    If not, should such patterns be defined by TMF OpenAPIs?

    Thank you,
    Lutz



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    Lutz Bettge
    Deutsche Telekom AG
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  • 2.  RE: Format for telephone numbers

    TM Forum Member
    Posted Mar 28, 2023 09:58

    I am only familiar with the US telephone industry. Internal to today's network it's just a string of digits. With older US telephone networks these had real meaning, but there is less technical division today. We continue to split them into groups to make them easier to read and remember. US phone numbers are divided into a 3-digit NPA (Number Plan Area, aka "area code), 3-digit NSS (Exchange), 4-digit Subscriber or Station Identifier. In the US and Canada (which share Country Code 1) the country code is often omitted. The only meaningful ranges of numbers in the US are in the 4-digit subscriber, as these may be within "private branch exchanges", which are internal telephone switching centers used within companies.



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    Andy Fuller
    AT&T Inc.
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  • 3.  RE: Format for telephone numbers

    TM Forum Member
    Posted Mar 29, 2023 04:45

    As mentioned earlier  ITU E.164 is the international standard.

    Informative overview on Wikipedia at  E.164 - Wikipedia however this does not express search parametes . that is really a local matter . Whether this should be in the TMForum documents depends on a member making a proposal.



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    Dave Milham
    TM Forum, Chief Architect
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  • 4.  RE: Format for telephone numbers

    TM Forum Member
    Posted Mar 29, 2023 05:31

    Thank you!

    As mentioned, we are already using the pattern derived from E.164; my question concerned the representation of number ranges, and it was not meant as search parameter, but we are assigning whole blocks of numbers to business customers, so we need to express that in the response e.g. in an ProductOrder, in the Inventory etc. So we need an attribute or characteristic representing not the individual number, but the block as a whole.

    I understand that there is no standard like E.164 that defines how to represent a block?



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    Lutz Bettge
    Deutsche Telekom AG
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  • 5.  RE: Format for telephone numbers

    TM Forum Member
    Posted Mar 30, 2023 05:35

    I did notice a discuss n the structure of e.164 in regex at

    Regular Expressions for ITU E.123 and E.164 phone number formats – SecureAuth Support

    So the block allocation and quarantining would have to align with those so not just a simple string. Maybe e.164 blocks need to be represented s concatenation of several string flowing this regex proposal?



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    Dave Milham
    TM Forum, Chief Architect
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  • 6.  RE: Format for telephone numbers

    TM Forum Member
    Posted Mar 30, 2023 14:49

    Bear in mind that the TMF models need to cover a variety of jurisdictions. The Open API model is non-opinionated regarding formats of addresses, phone numbers, etc.

    You can always make extensions to the model to meet your local needs.



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    Jonathan Goldberg
    Amdocs Management Limited
    Any opinions and statements made by me on this forum are purely personal, and do not necessarily reflect the position of the TM Forum or my employer.
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