braun@dri.com (Kral) (04/30/91)
I need to update my list of ccitt standards. Here is what I have (below); if anyone has a superset list, or anything they can add to it, I would appreciate it. CCITT-standards V.21 300 bps V.22 1200/600 bps FDX V.22bis 2400 bps V.23 1200/75 bps (host tx 1200, rx 75, terminal tx 75, rx 1200) V.24 known as EIA RS-232 in the USA V.26 2400 bps 4W V.26bis 2400/1200 bps HDX V.26ter 2400/1200 bps FDX V.27 4800 bps 4W V.27bis 4800/2400 bps 4W V.27ter 4800/2400 bps FDX V.29 9600 bps 4W V.32 9600/4800 bps FDX V.33 14.4 kbps V.35 48 kbps 4W V.36 48 kbps 4W V.37 72 kbps 4W V.17 V.17 is the new modulation scheme that provides 12000 and 14400 bps trellis-coded modulation for Group 3 facsimile. CCITT Recommendations T.4 and T.30, which define Group 3 fax, have also been amended to reference V.17 and provide for negotiation of its use (and those amendments have been adopted as well). V.17 also adds trellis-coded modulation at 7200 and 9600; these speeds are also provided in Group 3 fax by V.29 modulation but without trellis coding. V.17 should thus allow these speeds to be used on somewhat worse lines than was previously possible. V.32 V.32bis is an extension of CCITT V.32 which adds speeds of 7200, 12000, and 14400bps, full-duplex on two-wire dial-up or leased lines. V.32bis also adds a "rapid rate renegotiation" feature which allows the modems, by mutual agreement, to shift data rates up or down through a simple signalling process that takes about 1/10th of a second; V.32 requires a full retrain, which takes from 5 to 10 seconds, in order to change speeds. thanx, -- kral * 408/647-6112 * ...!uunet!drivax!braun * braun@dri.com Whoever is calm and sensible is insane -- Rumi