The DGH A1000 Series RS-232 to
RS-485 Serial Communications Converters boxes will convert
RS232 signal levels to the correct electrical signals required by
RS485. RS485 is recommended when many DGH modules, or other addressable
devices, must be connected to a host computer over long distances. The A1000
converters allow communications bus lengths up to 4,000 feet and baud rates up
baud using one twisted pair of wires.
RS485 allows bi-directional data on the same pair of wires,
therefore some means of arbitrating the data direction is required. The A1000 converters automatically control the bus direction without the need for external
handshaking signals from the host computer. Therefore, host software written for
half-duplex RS232 may be used without modification. The RS485 bus control is completely
transparent to the user.
Use the CA-2 cable to
connect to a host computer 9 pin serial port.
The A1000 can also operate as an RS-485 repeater. RS-485
repeaters are required to extend communications bus lengths or allow more than 32 devices
to be connected to a communications bus.
The A1000 contains
an internal +24Vdc one amp power supply for powering DGH modules.