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  2. Telephone exchange names - Wikipedia

    en.wikipedia.org/wiki/Telephone_exchange_names

    Telephone numbers listed in 1920 in New York City having three-letter exchange prefixes. In the United States, the most-populous cities, such as New York City, Philadelphia, Boston, and Chicago, initially implemented dial service with telephone numbers consisting of three letters and four digits (3L-4N) according to a system developed by W. G. Blauvelt of AT&T in 1917. [1]

  3. Main distribution frame - Wikipedia

    en.wikipedia.org/wiki/Main_distribution_frame

    The MDF is a termination point within the local telephone exchange where exchange equipment and terminations of local loops are connected by jumper wires at the MDF. All cable copper pairs supplying services through user telephone lines are terminated at the MDF and distributed through the MDF to equipment within the local exchange e.g. repeaters and DSLAM.

  4. List of country calling codes - Wikipedia

    en.wikipedia.org/wiki/List_of_country_calling_codes

    Worldwide distribution of country calling codes. Regions are coloured by first digit. Country calling codes, country dial-in codes, international subscriber dialing (ISD) codes, or most commonly, telephone country codes are telephone number prefixes for reaching telephone subscribers in foreign countries or areas via international telecommunication networks.

  5. Public switched telephone network - Wikipedia

    en.wikipedia.org/wiki/Public_switched_telephone...

    Public switched telephone network. The public switched telephone network (PSTN) is the aggregate of the world's telephone networks that are operated by national, regional, or local telephony operators. It provides infrastructure and services for public telephony. The PSTN consists of telephone lines, fiber-optic cables, microwave transmission ...

  6. List of telephone exchanges in London - Wikipedia

    en.wikipedia.org/wiki/List_of_telephone...

    London manual exchanges were gradually converted to Director automatic exchanges from 1927. Holborn was the first, at midnight on Saturday 12 November, a local and tandem exchange. Bishopgate and Sloane exchanges followed in six weeks, then Western and Monument exchanges. The London area contained 80 exchanges, and full conversion was to take ...

  7. List of international call prefixes - Wikipedia

    en.wikipedia.org/wiki/List_of_international_call...

    This is a list of international dialing prefixes used in various countries for direct dialing of international telephone calls.These prefixes are typically required only when dialling from a landline, while in GSM-compliant mobile phone (cell phone) systems, only the symbol + before the country code may be used [citation needed] irrespective of where the telephone is used at that moment; the ...

  8. List of file formats - Wikipedia

    en.wikipedia.org/wiki/List_of_file_formats

    ARC – Nintendo U8 Archive (mostly Yaz0 compressed) ARJ – ARJ compressed file. ASS, SSA – ASS (also SSA): a subtitles file created by Aegisub, a video typesetting application (also a Halo game engine file) B – (B file) Similar to .a, but less compressed. BA – BA: Scifer Archive (.ba), Scifer External Archive Type.

  9. North American Numbering Plan - Wikipedia

    en.wikipedia.org/wiki/North_American_Numbering_Plan

    International access. 011. List of dialing codes. The North American Numbering Plan (NANP) is a telephone numbering plan for twenty-five regions in twenty countries, primarily in North America and the Caribbean. This group is historically known as World Zone 1 and has the telephone country code 1. Some North American countries, most notably ...