As has been said, the normal speed of that is 500 kilobits per second, but it can go faster.
The correct figure is 128 kilobits per second, not 28.
A computer using a standard phone connection can download up to 56 kilobits of information a second.
They must also provide audio channels and at least one return video channel and two-way data channels, some of which should have a signalling rate of 80 kilobits per second.
The raw (uncoded) physical layer bit rate is thus 31.5 kilobit/second.
The kilobit has the unit symbol kbit or kb.
