At&t Bell Laboratories

Radish Communications Systems, Inc.

Charles J Fette

Frank J Bogart

Richard A Davis

Ronald K Witmore

Anthony J Brittain

Keith S Knight

Thornton S Paxton

Peter Mathys

Karen L Page

Mary R Dedisse

Radhakrishna S Divakaruni

A telecommunication system provides voice and data communications over a conventional telephone line that can be dynamically switched from voice mode to data mode during a single conversation. Each station includes a telephone for voice communications and bypass relay means for selectively connecting the telephone to the telephone line in voice mode and disconnecting the telephone while operating in data mode. Prior to transmitting data, the originating station first transmits a start signal over the telephone line that includes a rate signal indicating one of the several possible data transmission rates. If a station detects a start signal transmitted by a remote station, a microcontroller directs the bypass relay means and modem to automatically switch from voice mode to data mode in preparation for receiving data from the originating station.

Telecommunication display system

An arrangement for according station and attendant feature transparency between independently operational PBXs of a PBX network. Each PBX includes a switch processor, station lines and tie-trunks extending to other PBXs. Each PBX also has a Direct Memory Data Controller (DMDC) for transmitting service or feature related data messages associated with tie-trunk calls to other PBXs over data links. On an interPBX call, the DMDC in a calling PBX transmits a data message to a DMDC in the called PBX over a direct link between the calling and called PBXs. In the event there is no direct link between the calling and called PBXs, the DMDC in the calling PBX transmits a message over a data link to a DMDC at a tandem PBX which, in turn, sends the message over a link to a DMDC in the called PBX. The DMDC in the called PBX processes the received data message and, by direct memory access, sends the message to its switch processor which provides the specified feature or other service required on the call above and beyond the establishment of a voice path connection between the calling and called stations. This arrangement allows interPBX calls to appear to the customers as if they are served by a single large PBX.

Providing feature transparency between a plurality of PBXs

Growing community of inventors

Parker, CO, United States of America

Charles J Fette