The image attached is the circuit that I found. Could anyone venture a guess as to what this might do based on the components and design? My guess is that it's some type of audio signal modulator, given the 1/8th audio jack ports and potentiometers.
•The board has four 1/8th audio jack ports, two are larger than the rest and have "N" and "M" stamped on them.
•It has one common power input used by most laptop chargers.
•It has one pushbutton switch.
•It has two 85k potentiometers.
•It has one small port on the side with two leads, probably relating to power input or output.
•It has a TDA7360 Audio Amplifier chip, a BUK573 MOSFET, a HCF4066 Quad Bilateral Switch, a MC14013B Dual Type D Flip-Flop, a LF347 Op-Amp (TI datasheet here).
Numbers: IS1, V2.1 REV 5A- Printed on the PCB
323276-004 REV B 5356 ASSEMBLED IN MEXICO- A label on the PCB
9544- Printed on bottom of PCB
That's all the information I have for now. If you think you know what it is but need more information, I'll attempt to disassemble the metal heatsink/housing to get a better look at the bottom. There are some amall logic chips visible on the obscured side.
EDIT: It has been suggested that I add a picture of the bottom of the board. Here it is.