Format of 10NET send record:
Offset	Size	Description	)
 00h 12 BYTEs	receiving node's ID
		if first byte has high-order bit set, message is directed to
		  the CT_RGATE vector at the receiver
		if second byte is 00h, first byte is taken as a CB
		  channel number and delivered to all nodes on same channel
 0Ch	WORD	 length of data at DX