The Model 63-2SA provides a hardware conversion for full duplex signals between RS-232 and RS-422 I/O ports. Since the RS-232 port may look like a computer or a modem, the converter is equipped with a DTE/DCE selector switch. The Model 63-2S will couple any RS-232C port with any RS-422 device, or two RS-232 devices over a greater distance when using two 63-2SA's back to back as line drivers. The 63-2SA contains TD and RD LED's to allow rapid verification of equipment performance. A programmable cable terminator provides the flexibility of mating with various cables.