Serial Interface of Laser Printer

[Caleb Hensley]

When a device is plugged into the RS-232 port of a laser printer, what utf-8 encoded bytes are sent to the device to request output?

I'm trying to imitate a printer's request for data through a script. I want to programmatically request data from a medical device at home so I can track the data from it from anywhere.

Does anyone have any ideas?

[Eli the Bearded]

In comp.periphs.printers, Caleb Hensley <calh...@gmail.com> wrote:
> When a device is plugged into the RS-232 port of a laser printer, what
> utf-8 encoded bytes are sent to the device to request output?

1. There's not a universal protocol for connection between a computer
and a printer even over a standard port. There may be a standard
way the data is sent, but the contents can vary. As the a trivial
example, the printer could speak Postscript or could speak PCL.
2. RS-232 ? Are you sure? Parallel ports are much more common for
old printers.
3. Printers that use old tech like parallel or RS-232 serial (instead
of USB serial or ethernet/wi-fi connections) are unlikely to
understand UTF-8 at all.

> I'm trying to imitate a printer's request for data through a script.

Use a standard printer interface like lp on Unix or prn on DOS.

> I want to programmatically request data from a medical device at
> home so I can track the data from it from anywhere.

Now I'm thoroughly confused about what you are trying to do.

Elijah
------
thinking maybe this isn't a standalone printer but part of some device

[Stuart]

In article <eli$21082...@qaz.wtf>,

Eli the Bearded <*@eli.users.panix.com> wrote:
> 2. RS-232 ? Are you sure? Parallel ports are much more common for
> old printers.

I only recall ever seeing one printer with an RS-232 interface. It was at
work and it was an Epson RX-80. The RS-232 interface was an add on option
available at extra cost from Epson.

--
Stuart Winsor

Tools With A Mission
sending tools across the world
http://www.twam.co.uk/

[Bennett]

Perhaps if a printer is not actually involved you could redirect the
output to a file.

Assuming a Windows ' cmd DOS box' type myfile.txt > newfile.txt
or something like Print /d:myprinter > newfile.txt

[Computer Nerd Kev]

Andreas Kohlbach <a...@spamfence.net> wrote:

> On Fri, 27 Aug 2021 20:27:28 +0100, Stuart wrote:
>> In article <eli$21082...@qaz.wtf>,
>> Eli the Bearded <*@eli.users.panix.com> wrote:
>>> 2. RS-232 ? Are you sure? Parallel ports are much more common for
>>> old printers.
>>
>> I only recall ever seeing one printer with an RS-232 interface. It was at
>> work and it was an Epson RX-80. The RS-232 interface was an add on option
>> available at extra cost from Epson.
>

> Yeah. Back in the day Centronics ruled the market.

Tandy used RS-232 for connecting printers to their Color Computer
line. As such I've got a dot-matrix printer with an RS-232 serial
port next to me now, though like a normal person I hooked it up via
the alternative (not quite IBM PC compatible, I had to build my own
cable) Centronics parallel port instead.

I was going to use it for printing onto carbon paper customs forms
for international postage. But just after I worked out how to
re-ink the ribbon, the Australian post office suddenly announced a
new online submission system. I won't complain too much - that was
the fun part, and the next step of working out the printer commands
to get all the text positioning just right promised a lot of
frustration (the manual's pretty good though).

--
__ __
#_ < |\| |< _#

[Stuart]

In article <sgc6lr$16j2$1...@gioia.aioe.org>,

Computer Nerd Kev <n...@telling.you.invalid> wrote:
> I was going to use it for printing onto carbon paper customs forms
> for international postage. But just after I worked out how to
> re-ink the ribbon,

Re-inking ribbons, now that takes me back. We used to buy bottles of
endorsing ink, the stuff used for rubber stamp pads, it was a messy
business but, like ink cartridges today, new ribbons cost more than they
should have done. The first printer I had was a Brother M1009, or a number
very like that, but re-badged by the outfit I bought it from.

[Hugh Hood]

Caleb,

It is possible to what you are requesting.

I've seen some medical devices (e.g. blood glucose monitors) with a
rudimentary serial port (RX,TX) that allow one to send a query command
at which point they will transmit data that can be received, buffered
and processed.

Unfortunately, most of those use proprietary commands and you must
request that information from the company. Some ingenious 3rd party guys
have used a serial port 'spy' to decipher those commands and have
released their own programs (usually low in cost) to use that
information as well.

As far as printers, I regularly use my HP LaserJet 4050TN with its
built-in RS-232 serial port with a legacy Apple IIgs computer, so it's
not unheard of. In that case, HP understands PJL commands and I can send
those and receive data back from the printer through the serial port.
Likewise, if it put the LaserJet in PostScript mode, I can use
PostScript commands to query the printer and receive data back.

It is doubtful that any medical device, however, will use either PJL or
PostScript.

So, to summarize, I would suggest you first contact the manufacturer's
support people to see if they would provide the information for you. If
not, check for 3rd party solutions and don't forget to check for
open-source software where the proper protocol will be disclosed.

Good luck.




Hugh Hood