ICD400A

ICD400A Quick Start Guide In Figure 6-2, the converter is set up to use internal bias and no termination with four wires. the impedance of the transmission line being used. Termination increases load on the drivers, requires installation complexity, changes biasing requirements, and makes system modification more difficult. Generally, termination should only be used for long distances. “If in doubt, leave it out.” ICD400A Isolated RS-232 to RS-422/485 Converter BLACK BOX ® This rugged panel-mount BLACK B converter offers 2 kV isolation. Withstands temperature variations from -40 to +176° F (-40 to +80° C). RS-485 4-wire DIP switch. Figure 6-2. RS-485 4-wire example. NOTE:  Shaded black means the DIP switch is ON. 8. Loopback Test/Troubleshooting Configure for RS-485 4-wire. Jumper terminals B to D and C to E. Connect a PC to the RS-232 port. TD and RD LEDs are ON when power is applied. RS-422 4-wire DIP switch. 7. Bias and Termination The circuit can be biased using the built-in 2 k-ohm pull-up and pull-down resistors. This is controlled with DIP switch position 5. The default setting is ON (bias resistors in). When an RS-485 network is in an idle state, all nodes are in listen (receive) mode. Under this condition, there are no active drivers on the network. All drivers are tri-stated. Without anything driving the network, the state of the line is unknown. IF the voltage level at the receiver’s A and B inputs is less than ±200 mV, the logic level at the outp...