Two Port RS-422/485 Serial USB Adapter Two independent RS-422 or RS-485 serial ports Capable of data rates up to 115.2 kbps Compatible with USB Specification 1.1 Plug & Play and Hot Swap capability Devices are enumerated as standard COM ports Full-duplex or half-duplex operation possible Automatic transceiver control in half-duplex operation possible Automatic transceiver control in half-duplex mode with DTR or RTS line Bus powered; no external power supply required Windows98 and Windows 2000 compatible
The DSU-200/300 provides two independent asynchronous serial interfaces to a PC via the USB port. Each of these ports can be used for either RS-422 or RS-485 communication. The adapter comes standard with two independent 16550 UARTs containing 16-byte FIFOs. These FIFOs, along with the FIFOs in the USB microcontroller, help to relieve the CPU of excessive interrupts by buffering received and transmitted data, making each channel capable of data rates up to 115.2 kbps.
To allow the continued use of existing application software designed for traditional serial adapter, the DSU-200/300 enumerates itself as standard COM ports. Thus, users can continue employing their presnet serial devices while at the same time taking advantage of the benefits that USB provides. For instance, users need not concern themselves with resource issues existing on the ISA bus when adding new devices--selecting I/O address and IRQ.
Another advantage of USB is PLug & Play capability; the user merely plugs the device in and it configures itself for operation. An additional user friendly is hot-swap capability; the computer need not be powered down before plugging in a new device.
The DSU-200/300 is completely compatible with USB specification 1.1. The adapter is bus-powered, so no external power supply in needed. Support is provided for Windows 98 and Windows 2000.