RS-232/422/485 Serial Communication USB Data Acquisition (DAQ) Products
ACCES I/O Products USB to Serial devices are designed for use with any computer system equipped with a USB port. Simply install the included software and connect the unit to your USB port and transform it into asynchronous serial ports for communication with serial instruments. 1, 2, and 4-port models are available offering users the choice of selectable RS-232, RS-422, or RS-485 protocols per port. All units include a rugged steel enclosure with attractive powder coat finish and anti-skid bottom and options for DIN-rail mounting and extended temperature.
Multiple peripherals such as POS, barcode scanners, scales, date-entry terminals, data acquisition modules, and automation equipment can now be recognized and used on a single USB port. It is now easier than ever to add serial ports and serial devices to any application with the trouble-free plug-and-play and hot-swapping features USB provides.
RS-485 and RS-422 have significant advantages over RS-232 as they use differential drivers instead of driving just one wire. This allows the cables in RS-485 and RS-422 applications to be up to 4000 feet, where RS-232 has a limit of 50 feet. See the table below for a comparison of cable length vs. baud rates.
|USB-232-IND||Rugged, extended temperature, single USB to RS-232 serial port adapter|
|USB-422-IND||Rugged, extended temperature, single USB to RS-422 serial port adapter|
|USB-485-IND||Rugged, extended temperature, single USB to RS-485 serial port adapter|
|USB-COM-2SM||Two-port USB to serial RS-232/422/485 adapter|
|USB-COM232-4A||Four-Port USB to serial RS-232 adapter|
|USB-FLEXCOM4||Four-Port USB to Serial RS-232/422/485 adapter|
|USB-IIRO4-2SM||Two-Port USB to Serial RS-232/422/485 adapter with 4 electromechanical relays and 4 optically isolated inputs.|
|Baud Rate||Standard Divisor||Divisor x4||Divisor x8||Maximum Differential Cable Length*|
|*These are theoretical maximums based on typical conditions and good quality cables based on the EIA 485 and EIA 422 standard for balanced differential drivers.|