The convertor should work, but it is a RS-422 convertor if I remember correctly. It will need a RS-232 adapter and a special cable as well. The note below might help you out a bit. The Diagnostic, Power, and possibly the Run lights should be lit. The Toggle switch should be in the online position, on DIP switch block one (toward top of unit) the only switches that should possibly be on are #6, 3, 2, and 1. DIP switch block two is used to set the station ID. This same address must also be used when settingup the link in Logicmaster. Zero is not a valid address. You must use a RS-422 converter such as FA-UNICON with the S2-25P-CVR adapter (Included with the FA-UNICON). It also helps to power up the PLC and DCU at the same time. NOTE: If the customer has a GE DCU, all GE DCUs are RS-422. If you need the RS-422 to RS-232 convertor mentioned in this note, you can get it at Automationdirect.com. Here is an application note that might help as well, although it is for an AutomationDirect PLC, it should work much the same way.