56 kbps
<communications> (56 kilobits per second) The data capacity of a normal single channel digital telephone channel in North America.
The figure is derived from the
bandwidth of 4 kHz allocated for such a channel and the 16-bit encoding (4000 times 16 = 64000) used to change
analogue signals to digital, minus the 8000 bit/s used for signalling and supervision.
At the end of 1997 there were two rival
modem designs capable of this rate:
k56flex and
US Robotics'
X2.
In February 1998 the
ITU proposed a 56kbps standard called
V.90, which is expected to be formally approved during September 1998.