laser printers and 8 bit serial (TANDEM)

[Greg McGary]

>	From: Joaquim Martillo <martillo at mit-athena.uucp>
>
>	I  should  think  (not having tried this) that setting the
>	/dev/tty into RAW|TANDEM  would  get  eight  bits  transmitted
>	and  the  the   device start/stop requests would be honored.

Please read the 4.xBSD manual page tty(4) in reference to TANDEM:

	In this mode the system produces a stop character (default ^S)
	when the input queue is in danger of overflowing, and a start
	character (default ^Q) when the input has drained sufficiently. 
	This mode is useful when the terminal is actually another machine
	that obeys the conventions.

In RAW mode, the tty has an 8-bit data-path in both directions, but
does not honor any start/stop requests.  In TANDEM mode, the tty
sends start/stop characters to the other end of the line whenever it
notices that its raw input queue is getting full or getting low.  The
state of the RAW flag {en,dis}ables a tty's response to flow control
requests, TANDEM {en,dis}ables a tty's generation of flow control
requests.

To wit, the TANDEM and RAW flags are orthogonal and have no direct
influence upon one another.  

Greg McGary
Locus Computing Corporation				       lcc!gm at ucla-cs
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