Format of DESQview/X socket interrupt handler entry:
Offset	Size	Description	)
 00h  3 BYTEs	near jump or short jump + NOP to actual interrupt handler
 03h	WORD	offset from following pointer for initial top of local stack
 05h	DWORD	pointer to argument/stack block (see INT 15/AX=DE2Eh)
 09h  7 BYTEs	signature "dvxunix"