1. 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. [ NTIA ] [ RR ] 2. The process by which fixed graphic images, such as printed text and pictures, are scanned, and the information converted into electrical signals that may be transmitted over a telecommunications system and used to create a copy of the original, or an image so produced. ( 188 ) Note 1: Wirephoto and telephoto are facsimile via wire circuits. Radiophoto is facsimile via radio . Note 2: Technology now exists that permits the transmission and reception of facsimile data to or from a computer without requiring hard copy at either end. Note 3: Current facsimile systems are designated and defined as follows:
Group 1 Facsimile: The mode of black and white facsimile operation , defined in CCITT Recommendation T.2, that uses double sideband modulation without any special measures to compress the bandwidth . Note 1: A 216 × 279-mm document, i.e. , an 8½ × 11-inch document, 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 216 × 279-mm documents in 3 to 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.
Group 2 Facsimile: The mode of black and white facsimile operation , defined in CCITT Recommendation T.3, that accomplishes bandwidth compression by using encoding and vestigial sideband , but excludes processing of the document signal to reduce redundancy . Note: A 216 × 279-mm document, i.e. , an 8½ × 11-inch document, may be transmitted in approximately 3 minutes using a 2100-Hz AM/PM/VSB, over a telephone -type circuit .
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