All WindSonics (option 1 or option 4) are shipped from Campbell Scientific with an interface cable. If the cable has been lost, order a replacement. Order model WINDSONIC1CBL-Lxx for an option 1 or WINDSONIC4CBL-Lxx for an option 4, where xx is the cable length. The maximum cable length is 50 feet for option 1. The maximum cable on the SDI-1 bus is 200 feet.