The K&K Systems CrossLink is a small USB-connected atteanna that allows access the CrossTalk device that controls solar sign alerts without the need for online service. The CrossLink plugs into a computer's USB port and sends a signal to the CrossTalk device that is within approximately 750 feet. This system is perfect for areas where internet access is weak or inaccessible. CrossLink is your gateway to setting schedules or activating sign alerts during special events using K&K's CrossTalk software that is installed on your computer. The CrossLink uses an on-board long range 900MHz local-area wireless connection to a primary unit. CrossTalks can be grouped which allows you to set the functions for multiple signs without having to program individual units.