laptop hdmi to sdi

I have a hdmi to sdi mini convertor but cant get the output to my Panasonic 410 switcher
This same converter works with other devices but not with any laptop? ??

Pls help

Is your laptop configured in one of the supported video modes for the converter? Check the tech specs for the converter here and you will find it only supports "video" resolutions and modes. So you will likely have to configure the laptop to output a very specific "video" format/resolution (e.g.. 1280x720 or 1920x1080 and at 60hz or 30hz.. or something like that).