SparkFun RJ11 Breakout Board - 6-Position Modular Jack PCB 20a Controller output: Digital switching output

Controller output: Digital switching output ( 0 and 1 )

Integrated 520 KB SRAM

with a grippy shaft and it comes with an on-off switch

With this cobbler from Adafruit Industries

and even educational purposes

SparkFun RJ11 Breakout Board - 6-Position Modular Jack PCB 20a Controller output: Digital switching outputRJ11 Breakout Access Telephone Sensor Jack Pins The SparkFun RJ11 Breakout gives you easy breadboard access to the 6 pins of a standard RJ11 (telephone style) jack. Useful for interfacing with RJ11 connected sensors, phone line projects, weather station consoles, and any device that uses an RJ11 connector for data. Technical specifications Connector RJ11 6P6C jack Output 6 breakout pins (breadboard friendly)