The present invention discloses a
data transmission method, device and
system, belonging to the communication technology field. The method comprises: a
data transmission device requires obtaining the
bus ownership of a
USB, divides the data to be sent into a plurality of bytes and generates a plurality of check bits, each
byte corresponds to one check bit; and a plurality of types and a plurality of check bits are transmitted through an assigned
signal line, wherein after the nth
byte in the bytes is transmitted, the nth check bit corresponding to the nth
byte and at least one assigned time pulse are transmitted, and then the (n+1)th byte is transmitted until the transmission of the bytes and the check bits are completed, wherein n is a natural number. The
data transmission device charges a first device through the
USB at present, or the first device charges the data transmission device through the
USB at present. Through adoption of the
baseband transmission technology, the data transmission method, device and
system can realize the dual-way communication on one
signal line and do not need modulation and
demodulation in the communication process so as to simplify the data transmission process.