Tag-Connect is a special type of connector with a tiny footprint. On our aconno programmers, we use Tag-Connect. Whereas its main competitor JTAG has a much bigger footprint and 2.54mm pitch, Tag-Connect has pogo-pins (spring-pins) and 1.27mm pitch. Tag-Connect cables are currently available in two versions: 'Legged' (TC2030-MCP) and 'No Legs' (TC2030-MCP-NL). Both have a Tag-Connect connector on one end, and an RJ12 (6-pin modular plug) on the other directly compatible with Microchip In-Circuit Debuggers and Programmers.
More info on Tag Connect can be found here.