Help with On-Line Indicator for Jabra GN8530e headset

I have a Jabra GN9350e headset that I use at work, both with my desk phone and USB on my workstation. Jabra sells an on-line indicator (, but it's just a plastic stick that lights up at the top. No one will understand what it is, or what it means. I intend to build an LED box that says something to the effect of 'ON A CALL' with a chasing border to get attention and deliver the message that, well, I'm on a call.

The tricky part for me is that I can not tell what type of connection is used to connect the device to the base station. I know it is a 2.5mm TRS connection, but am unsure if it is stereo or mono flavor. I am also unsure what the actual signal would be - is the sleeve is ground, tip signal, etc. I have spent a few hours searching the web and found nothing.

My end goal would be to build a plastic box to house the indicator assembly, with mirrored plastic on the front so that when the indicator is off it would appear to just be a black box. When active, there would be a chasing light border (two or three LED sequence, just regular chasing lights), and a solid on field in the middle with verbage. I'm good with a soldering iron, but new to this kind of build.

If someone could assist / recommend how to proceed in building the circuitry that could connect the LED's together (sure I can find that information on this site elsewhere) that would be nice, but primarily I would need help interfacing the indicator with the headset base station.