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 to 115.2K 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.
• Completely transparent to host software
• No external flow control signals required
• Optically-isolated bidirectional data flow
• Standard baud rates: 300 to 115K baud
• Automatic internal RS-485 bus supervision
• Networking up to 4,000 feet
• Transient suppression on RS-485 data lines
• Internal jumper selectable termination resistors
• Internal 1KW biasing resistors on RS-485 data lines