The GX5642 provides 128 digital Inputs or Outputs and direction. The figure below shows a typical I/O channel block diagram when the board is in Independent mode:
Typical Single I/O Channel
When the board is in Independent mode each channel can convert Differential to TTL (Differential port is input and TTL port is output) or TTL to Differential (TTL port is input and Differential port is output). Each channel has a dedicated DIP-Switch that sets the conversion direction for the channel upon power up. The user can preset each channel conversion direction by simply setting the specified channel’s DIP Switch to On position: Differential to TTL or Off position: TTL to Differential. The Differential I/O terminals are terminated with a built-in 100-Ohm resistor.