Monitor data line activity or connect 2 devices to one RS-232C port! Here is a simple, inexpensive way to "TAP" into a data line so you can see what's going on with a scope, or monitor a line without interrupting the flow of data. Three DB-25 connectors wired straight through, make "tapping" into existing RS-232 lines simple and neat. This handy little device can also be used anywhere you would use a "Y" cable, such as connecting 2 terminals in parallel to one port. All possible combinations of gender connectors and mating hardware. (Please specify genders: MF-M, MF-F, MM-M, MM-F, FF-M, FF-F).