Thanks. I modified the Device::ParallelPort::drv::linux module, and in the init() function I added the code: 
$this->{DATA}{DEVICE} = "lp0";

[download]
before the "linux_opendev" call, but the result is the same: I can't set (and probably get) the data bits (this is the result of your script almut): 
Data port:    ff  11111111
Control port: ff  11111111
Status port:  ff  11111111
set  bit 0 to 0
read bit 0:   1
set  bit 0 to 1
read bit 0:   1
set  bit 0 to 0
read bit 0:   1
set  bit 2 to 1
read bit 2:   1
Bit 0: 1
Data port:    ff  11111111
set data      'a' (0x61 01100001)
Data port:    ff  11111111
set control    4  (bit 2)
Control port: ff  11111111
Status port:  ff  11111111

[download]
I tried to change "lp0" in this->{DATA}{DEVICE} to "/dev/usb/lp0", but nothing changed... I think that my usb adapter is not so compatible with Linux or maybe it's not a really usb to parallel port adapter...

In reply to Re^2: use Perl With usblp Parallel Adapter by Morzilla
in thread use Perl With usblp Parallel Adapter by Morzilla

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.