If you're using a newer PC, then you don't have serial (RS232) ports - but you do have USB. You will need a USB-serial cable. Fortunately there are many off the shelf ones that have reportedly been used on older Unidens with great success. Some of them are listed in our wiki, along with some notes about loading drivers and using Windoze Device Manager...
Connecting scanners via USB - The RadioReference Wiki
Hopefully others will chime in here and recommend something that was successful with connecting to the BCT8. The USB-1 isn't rated to work with such an old scanner.