SIMULTANEOUS VOICE AND DATA ON THE GENERAL SWITCHED TELEPHONE NETWORKUSING FRAMED QADM

Considerable effort has been expended in recent years to allow voice t o be transmitted over a general switched telephone network (GSTN) conn ection simultaneous with modulated data. A new transmission technology for this purpose is introduced - framed quadrature audio/data modulat ion (framed QADM) - in which voice and data channels are combined as a n integral part of the modulation process. The basic technology is des cribed and two implementations, which are at different levels of matur ity for standardization within the International Telecommunications Un ion (ITU), are presented. Finally, system attributes are discussed for framed QADM as they compare to other technologies.