Brainboxes US-313 USB to Serial 2 x RS422/485

USB to Serial providing two RrS422/485 serial ports. Up to 921,600 data
transfer rates and the 128 byte deep transmit and 384 byte receive
FIFOS, coupled with 1Mbit line drivers deliver uncompromising
performance on your laptop/PC.

USB to serial is the quick low
cost way to connect your computer to a serial comms enabled device.
Boost software gives industry leading functionality and compatibility.

RS422
Standard: RS422 allows one transmitter and up to 10 receivers with data
transmitter rates up to 10 megabits per second for distances up to 40
feet and up to 100 Kilobits per second for distances up to 4000 feet
(1219 metres).To achieve good long distance noise immunity, 2 wires are
used to carry each signal, configured as a twisted pair of cables. The
TXD pair and RrXD pair are used to carry the data whilst the RrTS pair
and CTS pair lines are used for handshaking. Thus 2 twisted pairs are
used without handshaking and 4 twisted pair cable is used with
handshaking both these schemes allow full duplex data communications.

RS485
Standard: RS485, based on the RrS422 standard allows up to 32
driver/receivers pairs on a party line data bus. Whilst only one of
these should be transmitting data at any time, the rest can all
simultaneously listen to the data. Handshaking is performed by software
protocol. Two twisted pairs form a full duplex system. Often only one
twisted pair cable is used as the TXD and RrXD lines are tied together;
this is known as half duplex mode. Traditionally, the RrTS signal is
used as the party line control to tristate the PC’s transmitter, but in
multitasking operating systems like Windows or Linux the only reliable
method is hardware autogating. Brainboxes 485 products implement a state
of the art autogating circuit thus ensuring error free communications
in half duplex configuations.

These products do away with traditional issues with USB technology so you can buy with confidence!