try this first ...
hook a null-modem cable between the SLC and your computer’s comm port ... in RSLinx “add” a driver for “RS-232 / DF1” ... (note: different versions of RSLinx use different names – but this should be close enough to spot) ... when the little “name” box pops up, click OK to keep the default driver name ... on the Configuration screen that pops up, click the “Auto Configuration” button ...
cross your fingers ... if you’re lucky – you’re in ...
if this doesn’t work, let us know ... we can work you through this ...
(one big potential problem: if you’re using a USB-to-serial adapter as your computer’s “serial port”, then “auto-configure” probably won’t work ... because RSLinx “sees” the adapter connected to the port – and not the SLC) ...
the null-modem cable needs connections between pins 2-3; 3-2; and 5-5
next step ... once you've got RSLinx able to see the SLC processor ... go to RSLogix500 ... under "Comms" from the top menu, select "System Comms" ... navigate to the SLC and nail it down ...
now you should be able to go back to "Comms" and choose "Go Online" ... you may have to "create a new file" before the software will connect ...
let us know how it goes ... and don't forget to register on the forum ...