Sharp UX Fax Series

Overview of the UX line

The Sharp UX series is a family of standalone facsimile machines produced by Sharp Corporation and identified by the "UX" model prefix printed on units such as the UX-P200, whose operation manual is titled simply "UX-P200 Facsimile Operation Manual." Sharp built its dedicated fax machines under two prefixes, UX and FO, with the UX line consisting of compact desktop fax terminals typical of home and small-office use. Rather than a single product, the series covers many individual models released across the life of the analog fax market, ranging from film-ribbon (thermal-transfer) units to later plain-paper inkjet models. For that reason this page describes the line at the family level and does not assign any one model's specifications to the whole series. What the models share is conformance to the international Group 3 fax standard, which governs how they scan, compress, and exchange documents over ordinary telephone lines.

Group 3 standard and PSTN operation

Every Sharp UX fax machine is an ITU-T (formerly CCITT) Group 3 terminal. Sharp's UX-P200 manual lists the machine's compatibility as "ITU-T (CCITT) G3 mode" and its applicable telephone line as the "public switched telephone network," which are the defining traits of the Group 3 class. Group 3 itself is defined by two ITU-T Recommendations: T.4, "Standardization of Group 3 facsimile terminals for document transmission," which specifies scanning resolution and image-coding schemes, and T.30, "Procedures for document facsimile transmission in the general switched telephone network," which specifies call setup, capability negotiation, and the handshaking protocol. Under T.4 a Group 3 page is scanned at 1,728 black-and-white picture elements across a 215 mm scan line, with a standard vertical resolution of 3.85 lines/mm and optional higher resolutions of 7.7 and 15.4 lines/mm. The UX-P200 manual states the same figures in imperial units, listing 203 pels/inch horizontally (8 pels/mm) and 98, 196, and 391 lines/inch for standard, fine, and superfine modes, confirming that the line follows the Group 3 resolution set.

Image coding and modem speeds

Group 3 machines compress each scanned line with run-length coding defined in T.4: one-dimensional Modified Huffman (MH) and two-dimensional Modified READ (MR). The UX-P200 manual lists its compression schemes as "MR, MH, H2," reflecting this Group 3 coding. Transmission speed depends on the modem, and Group 3 modems are standardized in the ITU-T V-series: V.27ter (2,400 and 4,800 bit/s), V.29 (up to 9,600 bit/s), and the optional V.17 (up to 14,400 bit/s), as summarized in Garret Wilson's Group 3 reference. Modem speed therefore varies from model to model and is a per-unit specification rather than a family-wide one; the UX-P200, for example, is rated at 9,600 bit/s with automatic fallback to lower speeds. The later Super G3 extension adds the V.34 modem at up to 33,600 bit/s, which mFax reports on higher-end machines such as its FO-DC550, so Super G3 should not be assumed for every UX model.

Printing methods across the line

Because the UX series spans a long period, its models do not share a single printing technology. Many UX machines are thermal-transfer (film-ribbon) fax machines: the UX-P200, for instance, uses "thermal transfer recording," printing onto plain paper by melting ink from a Sharp imaging-film roll. Thermal-transfer models are recognizable by the film they consume; the UX-5CR roll is used by models including the UX-P100, UX-P115, UX-P200, UX-A255, UX-A260, and UX-CD600, while the UX-3CR film serves the UX-300/305/460 group, according to consumables listings. Later in the line Sharp moved some models to plain-paper inkjet printing, such as the UX-B700, per mFax's Sharp fax overview. For the mechanics behind these output methods, see the thermal printhead and inkjet printing references.

Models in the series

Representative members of the series include the UX-P100, UX-P115, UX-P200, UX-A255, UX-A260, and UX-CD600 (thermal-transfer models using UX-5CR film); the UX-300, UX-305, and UX-460 (thermal-transfer models using UX-3CR film); the UX-355L; and the plain-paper inkjet UX-B700. These model identities are drawn from Sharp documentation and consumables-compatibility listings. Individual units differ in memory capacity, document-feeder size, modem speed, display, and features, and this page intentionally avoids presenting one model's numbers as if they applied to the whole family. The common thread is the Group 3 fax engine rather than any shared print mechanism or feature set.

Consumables and media

On thermal-transfer UX models the consumable is a roll of Sharp thermal-transfer imaging film rather than toner or a liquid-ink cartridge. The UX-P200 manual specifies a UX-5CR replacement roll of about 164 ft (50 m) that yields roughly 150 letter-size pages; the UX-3CR film performs the equivalent role on the 300/400-series machines. Because these are plain-paper fax machines, the paper itself is ordinary copier stock: the UX-P200 tray is rated for about 50 letter sheets of 20-lb paper. Plain-paper inkjet models such as the UX-B700 instead use ink cartridges and carry a larger paper tray. Buyers of used units should confirm which film or ink a specific model takes, since the UX-5CR and UX-3CR supplies are not interchangeable across the whole line.

Availability and legacy

Sharp no longer manufactures its standalone UX and FO fax machines for retail. According to mFax's buyer's guide, remaining units are generally sold used or refurbished, and Sharp's current fax capability is delivered through its MX-series multifunction printers rather than dedicated fax hardware. Despite being out of production, UX machines remain usable because Group 3 is a stable international standard: any Group 3 terminal or fax service that conforms to ITU-T T.4 and T.30 can exchange documents with a UX machine over the telephone network. For wider context on the technology, see the reference pages on how fax machines work and on analog versus digital fax.