Int 7A  - Novell Netware - Spx Driver - Listen For Spx Connection          [N]

   BX = 0012h
   AH = watchdog flag (00h disabled, 01h enabled)
   AL = retry count (00h = default)
   ES:SI -> Event Control Block (see #3481 at BX=0003h)

Return: nothing

Notes: there should always be at least two SPX ECB's listening to a socket, so
     that NetWare can perform its internal packet exchanges
   this function is supported by Advanced NetWare 2.1+

See Also: BX=0011h,BX=0013h,BX=0014h