This is possible a few different ways.
1. Use a TED or other type of wireless impulse transmission device and substitute it for the wire.
2. Record the splits with a TIMY, TDC, or any other syncronized timing device that can record bib and time stamps and import the splits into TTware after the race.
3. Use your wireless network with a TCP/IP to serial converter to have a split location timer available over the network. This would require another networked computer running TTware to work just the splits. It would look for the split timer and use its information while your finish timer would work just the finishes on a separate com port. You could get away without the TCP/IP converter if you had the split timing PC at the split location instead of the finish. This way it would connect to a timing device via standard com port.
Option 1 requires a wireless impulse transmission device and a local timer would be recomended but not required.
Option 2 requires a local timing device that can record bib and time information and dump it to a PC
Option 3 requires a local timing device and another PC with the TCP/IP to Serial converter needed if the PC is at the finish and not at the split location.