3DIN-191 & DIN-192 USERS MANUAL
GENERAL DESCRIPTION
The DIN-191 and DIN-192 series converter boxes convert RS-232 communications signal levels to the correct electrical signals required by RS-485. The RS-485 communications standard is recommended when many modules, or other addressable devices, must be connected to a host computer over long distances. The DIN-191 and DIN-192 converters allow communications bus lengths up to 4,000 meters and baud rates up to 115K baud using one twisted pair of wires.
The RS-485 communications standard is half-duplex; therefore data can be transmitted in only one direction at a time. To determine the direction of data on the RS-485 bus, many products require external handshaking signals to control the bus direction when transmitting or receiving data. This technique often requires that host RS-232 software be written, or modified, to accurately control handshaking signals for proper system operation. The DIN-191 and DIN-192 automatically control the bus direction without external handshaking signals from the host. Therefore, host software written for RS-232 may be used without modification. RS- 485 bus control is completely transparent to the user.
The DIN-192 is an RS-485 repeater. Repeaters are required to extend communications bus lengths or allow more than 32 RS-485 devices to be connected to a communications bus. A repeater simply re-amplifies, or boosts, existing RS-485 signals transmitted over long distances.
The DIN-191 and DIN-192 are each isolated between the RS-232 port and/or RS-485 ports and require a regulated +5Vdc power supply.