Bitfields for SK-UPPS protocol mode:
Bit(s)	Description	)
 0	promiscuous mode; protocol receives all frames regardless of their
	  destination (PROTOCOL TYPE must be FFFFh)
 1	if set, protocol's Event Upcall will be called on entry and exit of the
	  DLI's Interrupt Service Routine (see #03854)
 2	DLI 2.2+ hook mode; protocol receives all directed frames destined for
	  this station (PROTOCOL TYPE must be FFFFh)
 3	DLI 2.3+ receive error frames (only valid in promiscuous mode (0))
 4-5	DLI 2.5+ frame type:
	00 Ethernet II; specify type code in PROTOCOL TYPE field (high-low)
	01 IEEE 802.2; specify Service Access Point (SAP) in MSB
	      (offset 0) of PROCOTOL TYPE field; LSB must be zero
	10 IEEE 802.2 with SNAP header; specify type code in PROTOCOL TYPE
	      field (high-low)
	11 reserved (currently unused)
 6	DLI 2.5+ if set, protocol's Event Upcall will be called with event code
	  EV_BUFFER_WANTED, when DLI runs out of Mbufs
 7	DLI 2.7+ chain mode; if set, client allows the specified frame type to
	  be shared with other clients
 8	DLI 2.8+ receive non-LLC frames rather than LLC frames
 9	DLI 2.8+ receive all multicast frames (see also AX=0009h)
 10-15	reserved (currently unused; must be zero)
Notes:	If PROTOCOL TYPE is FFFFh and neither the "promiscuous" nor the "hook"
	  mode is set, the protocol receives all frames that did not match
	  any registered frame type (demultiplexor mode).
	Protocols using "promiscuous", "hook" or "chain" mode should always
	  return from the Receive Upcall with the received Mbuf in ES:BX and
	  the Carry Flag set. The DLI will then pass the Mbuf to the FEED BACK
	  BUFFER function (see AX=000Fh).
	Some DLIs do not support all or even any of the "promiscuous",
	  "receive non-LLC" and "receive all multicasts" mode bits.
SeeAlso: #03849