Browse Prior Art Database

Voice and Data Transmission

IP.com Disclosure Number: IPCOM000042834D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Abbiate, JC: AUTHOR [+3]

Abstract

This system enables the transmission of digitized voice information and pure data over the same channel. The voice terminals are connected to the system through tie-lines and PBX, while pure data terminals are connected to the system through V24 CCITT interfaces. Priority should obviously be given to voice transmission. Therefore, the data are inserted within the bit flow based on voice activity detection information. The pure data rate is thus variable. Data information losses are avoided by providing the system with elastic buffering means which are loaded at two predetermined rates. Switching from one of the rates to the other is made dependent upon the elastic buffer contents. The system shown in the figure is made for processing one voice line and one data line only. Extension to several lines is straightforward.

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Voice and Data Transmission

This system enables the transmission of digitized voice information and pure data over the same channel. The voice terminals are connected to the system through tie-lines and PBX, while pure data terminals are connected to the system through V24 CCITT interfaces. Priority should obviously be given to voice transmission. Therefore, the data are inserted within the bit flow based on voice activity detection information. The pure data rate is thus variable. Data information losses are avoided by providing the system with elastic buffering means which are loaded at two predetermined rates. Switching from one of the rates to the other is made dependent upon the elastic buffer contents. The system shown in the figure is made for processing one voice line and one data line only. Extension to several lines is straightforward. Also, one should assume that the digital transmission is performed in the SDLC (Synchronous Data Link Control) mode wherein fixed length bit frames (20 ms long) are transmitted. A number of bytes are thus devoted to information, such as flags, headers and validity checking. The remaining bit positions are devoted to data bits, i.e., voice data, signalling data, and/or pure data. Three different SDLC bit frames may be provided, i.e., one for voice and pure data (during voice activity periods), one for signalling and pure data, and one for pure data only (during voice inactivity periods). The data to be transmitted is first...