The Picturephone System: Wideband Data Service

The rapid growth of data transmission over the past several years has indicated a need for finding more efficient means of transmitting large amounts of data. At present, the majority of data transmission occurs at rates of a few kilobits per second over voicegrade facilities. Modern computer-associated equipment is capable of operating at rates several orders of magnitude greater than this with no significant economic penalty. For data service at such high speeds, wideband private-line facilities are available. Additionally, a common-user switched wideband service, called Data-Phone 50, is presently available to provide 50-kb/s transmission capability over a four-city experimental network. Data sendee using the planned nationwide network of Picturephone facilities will provide speed capability an order of magnitude greater than this. Wideband data service over the Picturephone network begins with the offering of a switched 460.8-kb/s capability through use of the initial network of Picturephone facilities. Faster service at 1.344 Mb/s is anticipated as network improvements are made within the next few years. It is expected that provision of switched wideband data capability on the Picturephone network will be a significant step toward 667