Device::Modem::FAQ(3) User Contributed Perl Documentation Device::Modem::FAQ(3)

This is a Frequently Asked Questions list about "Device::Modem" perl extension.

"Device::Modem" is a perl extension written in pure perl that allows to communicate with modems, or generically with "AT command set compliant" devices connected to your computer via a serial port.

Cosimo Streppone (cosimo@cpan.org), an Italian guy, who works and enjoys writing perl programs and objects. If you want to know more, go to http://www.streppone.it/cosimo/work/perl/

If you are asking that, probably you are in the wrong place.

Perl is a wonderful programming language, that cuts development times, helps developer keep mental health, good life-style, doesn't pollute developer's mind, allows complete freedom of style, and (from perl manual), gives you enough rope to hang yourself.

Some starting points:

It is a set of standard commands, also called "Hayes", in which (almost) all commands begin with "AT" prefix and they allow to control a modem, router, whatever device. Also cellular phones work with a subset of standard "AT" commands.

What the heck are you doing here? http://www.google.com/search?q=Tech+glossary+modem

You must have:

  • A working computer with a standard RS-232 serial port
  • An AT-compliant device (a modem will do perfectly here :-)
  • A working Perl installation
  • "Device::SerialPort" module installed if you are on some unix platform. "Win32::SerialPort" module installed if you are on Win32 platform.

"Device::Modem" works close to the serial port communication layer, which varies on many platforms. It relies on "Device::SerialPort" and "Win32::SerialPort" modules for all low-level communication layer.

It tries to build a platform independent layer above these two low-level modules, so developers don't need to distinguish among different platforms.

It's been reported to work on "Win32", "Linux", "Mac OS X", "FreeBSD", "NetBSD", "OpenBSD", "ARM-Linux" and "Solaris".

Yes, it is allowed by its license, that is the same as Perl language. If you are using it in a commercial package, or plan to do so, please inform the author (Cosimo Streppone, cosimo@cpan.org <mailto:cosimo@cpan.org>). Thank you.

This is an open-source software developed in my little home spare time and for my personal interest and amusement. This module has a test suite, but it is not very extensive, so it is possible that some feature X does not work, or it is not implemented yet or I cannot test it.

If you are in this situation, please contact me <mailto:cosimo@cpan.org> and provide the following information:

  • Your operating system version and architecture. Complete output of "perl -V" command is good for this.
  • Your perl version. Again "perl -V".
  • Your "Device::Modem", "Device::SerialPort" and (if you are using it) "Device::Gsm" version. In case of doubt, send the output of: 
    perl -MDevice::Modem -le 'print Device::Modem->VERSION'

Thank you.

This is definitely reported to be working by several users, who also contributed patches and tested the feature.

Otherwise, just look at Aaron Mitti's Device::SerialPort::Xmodem CPAN module.

It might seem that XModem and ZModem should be well over dead at this point. But, looks like several old/new devices still support them.

So, ZModem support has been contributed by a user, and will be added to the main release Soon(tm).

First of all, be sure to use Device::Modem version 1.52+.

Probably you don't have the correct permissions to access your modem device (usually /dev/modem, or /dev/ttyS0 on unix and COM1/COM2/... on windows). Or you are trying to use the examples that come with Device::Modem distribution with an older version (Device::Modem <= 1.33).

In this case, you should upgrade to Device::Modem 1.52+.

Again, upgrade to Device::Modem version 1.52+.

If you get this error, it means that the communication port could not be opened. Most probably you don't have permissions to access your serial port, or you have used a wrong device name (check your device entry in "/dev" folder).

Since version 1.52, Device::Modem::connect() will try to automatically reconnect if your port connection shuts down, or the "Device::SerialPort", or "Win32::SerialPort" underlying object is deleted or invalidated.

You should really upgrade to Device::Modem 1.52+.

No. What you can do, is voice call dialing. After the dialing though, you have to speak. Your computer can not do that, unless you have a PBX board, at least not with Device::Modem.

Make sure you are using that latest version. From version 1.30, the main "send-command" / "wait-answer" cycle has been sensibly improved for speed, though you now have to specify a timeout if you want the module to wait an answer if modem is not ready.

Probably this is the better compromise...

Oh, yes! Please feel free to contact cosimo@cpan.org to decide details about this... :-)

Uh.

Please contact me, so I can improve my software design, ideas and coding, but only if you explain the reasons of your criticism. Thank you.

2023-07-25 perl v5.38.0