GG Labs T232
The circuit is trivial. Every line is connected to a LED through a 1Kohm resistor. One 9-pin resistor array is used to reduce the overall size. Multiple locations for the LEDs are provided to support standard 3mm round, rectangular and DIL LED arrays. Both regular LEDs and bi-color LEDs can be used.
DIP switch SW1 can be used to disconnect any of the signals that can be manually rewired using jumpers connected to J3 and J4.
For more permanent setups, SW1, J3 and J4 can be replaced with soldered jumper wires.