Sorry carlg I have been conducting a solder training class all week.
The AS-InterLink that Chuck mentioned would be what you would use to InterLink those two units but – the better option would be to Ethernet connect them using one of the AS-EC cables. These come in a variety of lengths or 2, 10, 15, 20 or 30 foot lengths. The part numbers will tell you which length they are: AS-EC-2E is a two-foot cable, the AS-EC-10E is a 10 foot cable… and so on. This is also the cheaper way to connect two units as well.