Format of FaxBIOS SLOG_OPEN, SLOG_CLOSE, RLOG_OPEN, RLOG_CLOSE command buffer:
Offset	Size	Description	)
 00h 12 BYTEs	common data (see #02935)
 0Ch	WORD	log handle
 0Eh	WORD	number of entries
 10h  6 BYTEs	future expansion
 16h	WORD	structure size