Tag connect is a special type of connector with tiny footprint.
On our aconno programmers we use Tag connect.
Whereas its main competitor JTAG has 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: