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Switched 56 is fantastic. You get a minimum of five times the amount of information transferred as you do on a standard analog phone line -- and in many cases […]

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.

Taking a unique approach, Newbridge Network Inc. and Ungermann-Bass Inc. (UB) have introduced complete system strategies that will allow users to trial asynchronous transfer mode (ATM) as a backbone technology […]

One can build a modem based on a single chip that transforms digital data into analog frequencies. It can transmit data at 300 baud asynchronous via telephone lines. The modem to be built is based on the MM74HC942 modem chip which provides ten to twenty-dB transmit carrier rejection. In the modulator section the frequency synthesizer generates clock frequencies for the sine-wave synthesizer. In originate mode the modem transmits in lower band and receives on upper band in answer mode these are reversed. The interface hardware between the HC942 and the IBM PC consists of decoding logic, a communication link and a tone dialer, and DAA. The modem circuit has few passive components. The modem's communications program has three routines. A listing of the communications program is included and also a diagram of the modem.

Micom Systems announced its Instanet 6000data PABX network which costs $7500. It uses standard telephone wiring and connectors. It accomodates up to 508 channels in one cabinet and operates at speeds up to 19,200 bps, full-duplex. It features the ability to restrict access and enforce security. A photograph of the unit is included.