Going for speed

As prices for communications equipment decrease and compatibility is resolved, high-speed dial modem installation will increase enormously. In November 1984, a 2,400-bps modem sold for $800; today, the same 2,400-bps dial modem costs less than $600. While there are several fast modems on the market, none have yet come to dominate. Most asynchronous modems use the Hayes Microcomputer Products AT command set, and the most popular error control technique is the Microcom Networking Protocol. High-speed (9,600-bps and above) modems can simulate full-duplex circuits; high-speed modems from several manufacturers are described. Digital transmission offers more speed than modems. AT & T's Dataphone Digital Service and similar offerings from Bell operating companies transmit at 56K-bps, often called wideband, that fits between the highest-speed modems running at 19.2K-bps and T1 switches running at 1.544M-bps.