SC139 is a serial 68B50 module designed for the RC2014 bus.

This serial module has a number of advantages over the standard RC2014 module. It has tight address decoding, flexible address selection, and its own clock. Having its own clock makes it independent of the CPU clock speed, allowing it to be used with faster (or slower) processors. In addition, the serial signals can be isolated from the RC2014 bus, via jumpers, allowing several of these modules to be connected to the same backplane.

The main features of this design are:

• Classic 68B50 serial port
• Tight address decoding
• Address selection via jumpers
• Isolation of serial signals via jumpers
• Compatible with RC2014 bus
• Hardware flow control in both directions
• Low profile RC2014 style design