PWM modulation WinPC-NC USB

Hello there,

Anyone with experience how to use the PWM mode on a laser with the WinPC-NC USB software?

I have a S 420 v.1 and use WinPC_NC v. 3.4 for the Laser I use a NEJE 20W (5,5W optic power) with TTL / PWM mode.
for generation of g-code I use the vectric Laser post processor "WinPC-NC ATC Arcs Laser No Z mm (*.nc)"

How can I use the PWM mode in combination with WinPC?
Witch pin do I use on the D15 connector (I assume pin 7 for PWM and pin for TTL mode) in combination with the GND?
What setting should I make in the WinPC programm to adjust the power of the laser (in M or G code )?
or should I make changes in the post-processor G-code?

Hope for some guidance in this.