[asterisk-biz] Knockoff TDM400 Cards - What's the Deal?

[Rusty Dekema]

I was wondering what the deal is with the knockoff versions of Digium
TDM400B cards and 1FXS/1FXO modules that one occasionally sees
advertised on this list.

Do these boards violate Digium's IP rights under US law?* Or did the
Digium TDM400 boards come from a Zapata/Zaptel or other open-license
design to begin with? I notice that the cards never seem to be sold by
US companies, yet they look virtually identical to the Digium
equipment...

*I know that no-one here can or will provide "legal advice";  I am
asking only in a general sense.

Thanks,
Rusty