Out of the box, the TS8000 uses the it's RS232 PGM port or the USB-B ports to be programmed with.
All other ports must be configured in DSI3 or DSI8000 in order to be used. This includes setting up the Ethernet port, other RS232 ports, or additional options your TS8000 may have come with.
Apply 24V, then use the PGM Port or USB (Type-B) first.
Depending on the model of your TS8000, the ports may be in a different order. Consult the TS8000 manual for pinouts and port locations.