Re: [PARPORT] Trying to print on a HP OfficeJet T45

Tim Waugh (
Sat, 16 Oct 1999 10:57:24 +0100 (BST)

On Thu, 14 Oct 1999, Iain McClatchie wrote:

> The lp driver seems to have grabbed the port okay:
> [> [iain@zippy ~]$ cat /proc/parport/0/devices
> lp
> [> [iain@zippy ~]$ cat /proc/parport/0/irq
> none

Looks good.

> The parport driver seems to understand that the printer wants to talk
> IEEE1284:
> [> [iain@zippy ~]$ cat /proc/parport/0/hardware
> base: 0x378
> irq: none
> dma: none

That isn't really what that means. The 'hardware' is the port itself (and
the chips inside the computer that drive it), not what's attached to it.
So that means that the parallel port chipset can do ECP; however, lp
doesn't use that, it just uses the SPP registers to drive the control
lines directly, byte by byte.

> I've configured /etc/printcap with ghostscript's cdj550c driver, which
> I'm guessing will talk to some subset of the printer's capabilities.
> I've turned on "Suppress Headers", "Send EOF after job to eject page",
> "Fix stair-stepping text", and "Fast text printing". I have no extra
> GS options.

The 'worse problems printing postscript' you mentioned probably boil down
to the cdj550c not being able to talk officejet language (but I'm

For text-only printing, that sounds fine.

> But after the printer ejects the page, it beeps and asks to be
> reconnected to the computer. My guess is that the printer is expecting
> some furthur IEEE1284 packets, transactions, whatever, and the kernel
> just stopping transmitting. So, I would imagine that I don't have a
> recent enough parport driver.

How odd. Well, we're only speaking 'compatibility mode' to the printer,
which is just a stream of bytes. I wonder why it thinks it's been

Perhaps it's trying to tell us something, and failing. Do you have IEEE
1284 'status readback' enabled? You could try something like:

# echo -ne 'hello, world!\014' > /dev/lp0
# cat /dev/lp0

> Reading the parport pages, there appears to be a fair bit of work
> recently on the parport driver. Does any of this work affect my
> ability to just talk PCL over ECP to my printer?

No, not really. PCL is for user-space to worry about, and ECP isn't
involved in this.

> I figure I'm missing some piece of driver software. Would anyone like
> to suggest what I should pick up? If it's experimental, that's okay.

It sounds a bit like that, yes. Have you tried asking on the officejet
mailing list?

> I suspect I may be one of the first people to try a T45 with linux, so
> I'm happy to experiment a little if I can get a bit of guidance.

How does the T45 differ from other officejets? I thought I'd heard
success stories from officejet owners, but perhaps I imagined them.


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This archive was generated by hypermail 2.0b3 on Sat 16 Oct 1999 - 06:30:27 EDT