The RSB Serial Booster was designed to drive up to 20 optoisolated NCD devices from a single RS-232 serial port with a DB9 connector.
The RSB has been tested to drive RS-232 signals at 1000+ feet at data rates up to 38.4K baud. Simply plug it into your RS-232 port, provide +12 volts to power the board, and run the In, Out, and Ground lines to all devices on the network.
NCD devices use an open-collector (O.C.) system for communicating data back to the computer. O.C. RS-232 signals allow several devices to share 3 data communication wires, but are NOT compatible with standard RS-232 signals.
The RSB serial booster is used to convert these O.C. signals back into PC compatible RS-232 levels. Note that this device cannot be used to send data from NCD devices back to a Macintosh computer, but has been tested to be fully compatible with all PCs.