If you are trying to connect to the DH+ port CH. 1, you will need a DH+ card in you r PC, with the appropriate cable. For a laptop, this would be a 1784-PCMK card with a 1784-PCM5 cable (this has a dongle on one end for the card and a DB9 on the other end) ans a 1784-CP7 adapter (DB9 to 8-pin mini-din). With this you would use the KT driver in RSLinx, configured for a device type PCMK. If you are trying to connect serially via the CH. 0 RS-232 port, you need a 1747-CP3 (or a standard null-modem cable). This port can be configured for either RS-232 DF1 or DH-485. For DF1, use the DF1 driver in RSLinx; for DH-485 use the 1747-PIC/AIC+ driver in RSLinx. You have a red DH+ LED on the CPU which is not normal. How is the PanelView 600 connected to the SLC (serial or DH+)? If it is connected to the serial port and you want to connect to the SLC over the serial port, post the full Catalog Number of the PV600; that will tell us if it is a DF1 or DH-485 device, which would help determine which serial driver you need to connect to the SLC.