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From: rjn@hpfcmp.UUCP
Newsgroups: comp.sys.hp
Subject: Re: Re: Review: HP LaserJet Series II
Message-ID: <1260005@hpfcmp.HP.COM>
Date: Fri, 20-Mar-87 11:26:04 EST
Article-I.D.: hpfcmp.1260005
Posted: Fri Mar 20 11:26:04 1987
Date-Received: Sun, 22-Mar-87 21:42:22 EST
References: <588@zen.UUCP>
Organization: Hewlett-Packard, Ft. Collins CO
Lines: 33

re: LaserJet status readback

>>                        We could  keep track of what has been sent to
>>   the LaserJet  but if it gets  switched  off the  computer  doesn't
>>   know.

>   The version of troff on this machine does keep track of which fonts
>   have been downloaded.  There is a command to reset that list if the
>   LaserJet is power cycled, and another command to inquire about presently
>   resident fonts.

Both of these comments really say the same thing.   Also, the commands
mentioned in the second paragraph are for an unreleased version of troff.
I'm not sure the four or so 3rd party troffs for HP9000 have this feature.

I suspect the history behind the lack of readback is related to:

* The RS-232C interface of LaserJet-I was developed by Canon.  They did
  not have HP's tradition of implementing the kind of status readback
  escape sequences most other HP terminals and printers have.

* The LJ-I was also designed for use with Centronics,  for which no 
  standard bidirectional I/O definition exists.

Now that the ScanJet has defined a form of Centronics input, and has
extended Printer Command Language (PCL) to include input,  perhaps we'll
see some status capabilities on future LaserJet class printers.  I know
that Boise division is aware of the need,  although I'm not privy to any
specific product plans on this issue.

Regards,                                              Hewlett-Packard
Bob Niland                                            3404 East Harmony Road
[ihnp4|hplabs]!hpfcla!rjn                             Fort Collins CO  80525