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Facsimile
  • A form of telegraphy for the transmission of fixed images, with or without half-tones, with a view to their reproduction in a permanent form. In this definition the term telegraphy has the same general meaning as defined in the Convention. (RR)
  • A system of telecommunication for the transmission of fixed images with a view to their reception in a permanent form. (JCS1-DoD) (JCS1-NATO)
  • The process, or the result of the process, by which fixed graphic material, including pictures or images, is scanned and the information converted into electrical signals that may be transmitted over a telecommunication system and used to record a copy of the original.
  • Note 1: Wirephoto and telephoto are facsimile via wire circuits; radiophoto is facsimile via radio. Note 2: Current facsimile systems are designated and defined as follows: (a) group 1 facsimile: A mode of black/white facsimile operation as defined in CCITT Recommendation T. 2, which uses double sideband modulation without any special measures to compress the bandwidth. Note 1: A 216 X 279 mm document (81/2 X 11 inches) may be transmitted in approximately 6 minutes via a telephone-type circuit. Additional modes in this group may be designed to operate at a lower resolution suitable for the transmission of documents 216 X 279 mm in a time between 3 and 6 minutes. Note 2: The CCITT frequencies used are 1300 Hz for white and 2300 Hz for black. The North American standard is 1500 Hz for white and either 2300 or 2400 Hz for black. (b) group 2 facsimile: A mode of black/white facsimile operation as defined in CCITT Recommendation T. 3, which accomplishes bandwidth compression by using encoding and vestigial sideband, but excludes processing of the document signal to reduce redundancy. Note: A 216 X 279 mm document (81/2 X 11 inches) may be transmitted in approximately 3 minutes using a 2100-Hz AM/PM/VSB, over a telephone-type circuit. (c) group 3 facsimile: A mode of black/white facsimile operation as defined in CCITT Recommendation T. 4, which incorporates means for reducing the redundant information in the document signal using a one-dimensional run-length coding scheme prior to the modulation process.
  • Note 3: A 216 X 279 mm document (81/2 X 11 inches) may be transmitted in approximately 1 minute or less over a telephone-type circuit with twice the group 2 horizontal resolution; vertical resolution may also be doubled. Note 4: Group 3 machines have integral digital modems. Note 3: An optional two-dimensional bandwidth compression scheme is also defined within the group 3 facsimile specification. (d) group 4 facsimile: A mode of black/white facsimile operation as defined in CCITT Recommendations T. 5 and T.
  • Note 5: Uses bandwidth compression techniques to transmit an essentially error-free 216 X 279 mm (81/2 X 11 inches) document at a nominal resolution of 8 lines/mm in less than 1 minute over a public data network voice-grade circuit.