U. S. Robotics 56Kbps modem
Preview by Al Giovetti, 10/26/96
Genre: POTS Modem
Release: January 1997
Developer: U. S. Robotics
Publisher: U. S. Robotics
Requirements: POTS (plain old telephone service) telephone lines, serial communications port, serial cable,
Standard ISDN (Integrated Services Digital Network) connections to the internet run at 64 Kbps and the prices require payment for each minute of local service and a special hookup fee. ISDN also has the disadvantage of requiring special phone lines and jacks when compared to modems that work over POTS. The new U. S. Robotics digital modem runs at 56 Kbps, which is only 8 Kbps slower over POTS (plain old telephone service) which has no local service charges or special hook up fees.
Similar to ADSL (Asynchronous Digital Subscriber Lines) which can produce speeds up to 4 Mbps in one direction, the new U. S. Robotics modems will support 56 Kbps when receiving signal (downstream or download) and 28.8 or 33.5 Kbps when sending signal (upstream or upload). The download signal bandwidth is most critical to internet users since most of the information moves in the download direction. The upload information is often just commands to initiate the downloads.
If you adopt the new U. S. Robotics standard, which could conceivably increase to 112 Kbps within the next year, much of the desirability of ISDN is compromised. Many people who have invested in ISDN may find themselves switching to these less expensive modems. One of the reasons for you to switch are the large numbers of providers who have committed to supporting the new standard. America Online, Compuserve, Netcom, and others.
The downside of the new modems is the lack of utilization of duplex systems which use one modem and two POTS phone lines which is a quick and easy way to get bandwidth. Some of the current protocols require two accounts with an ISP and two 28.8 Kbps modems to get the 56 Kbps speeds. With the new U. S. Robotics modems, the elusive 126 Kbps speed is within reach using this duplex system. The downside is that many online services are not supporting this duplex standard.
Another problem is that the U. S. Robotics protocol is not yet accepted by the modems standard setting bodies. Many of the other modem manufacturers want to wait until uniform standards are set prior to coming out with the newer faster modems. The telecommunications regulatory organizations include the Telecommunications Industry Association and the International Telecommunications Union.