HOWTO: Internet access by modem

Dialup by analog modem

I originally designed Puppy to access the Internet by conventional modem dialup to an ISP (Internet Service Provider), over the Public Switched Telephone Network (PSTN). The modem is called an analog modem, as it sends and receives data by audible-frequency tones -- which you can hear as the modem dials the ISP.

I have moved on to various modes of digital broadband access, however many people, in certain parts of the world, are still on analog dialup. Therefore, this section is still very relevant!

Traditionally, Linux only really worked with what we call "hardware" serial modems -- whereas many modems are what is called "soft" modems, only sold with drivers for Microsoft Windows. If your PC has an internal modem, or a external modem attached via a USB cable, it is most likely a soft-modem.
Please note that I am describing analog modems here, for dialing-up an ISP (Internet Service Provider) -- these are different from 3G, ADSL and cable modems that are used for broadband digital Internet access.

• External serial modem. If you have an external serial modem, it is easy to recognise by the distinctive cable -- fairly large flat rectangle shape, with 9 or 25 pins. This is a hardware modem, and will definitely work with Puppy.
• Internal PCI modem card. 'PCI' refers to the sockets on the motherboard, into which an internal modem can be plugged. Up until about 2002, true hardware PCI modems were manufactured, since then they have all been soft-modems -- so that's most likely what you have.
• Modem built-in to the motherboard. Technically, these are still PCI modems, as the term "PCI" actually refers to the main interface bus on the motherboard, to which all input/output devices are connected. These are all soft-modems.
• External USB modem. These days USB is used for almost all external devices -- mouse, keyboard, modem, printer, scanner. There are some true-hardware USB modems, but most likely it is a soft-modem.
• PCMCIA modem. Also known as cardbus. This is a socket on laptops. These can be soft or hard, the modern ones likely to be soft.

The real down-side of a soft-modem however, is that to make the CPU do some of the processing work requires a special driver for that particular modem, and most manufacturers have only bothered to write drivers for Windows. However, some manufacturers have become more "Linux aware" and also some Linux enthusiasts have developed drivers.

Be warned, if you have a soft modem, it may not work with Puppy. Puppy-enthusiast 'ezeze5000' (forum name) sent me half-a-dozen old PCI soft-modem cards to test. That was in 2008, and at that time I only got one of them to work in Puppy. Since then, the success-ratio has improved, and in 2010 I have got half of them to work.

Note, if a soft-modem does work in Linux, there is a jargon name used for it -- it is called a "linmodem".

'Dialup' by wireless modem

Wireless modems are often referred to as 3G modems or HSDPA modems. In a nutshell, they give you Internet access without needing wiring. They also require a "dialup" operation similar to analog modems, so in Puppy we are able to use the same PupDial GUI tool for both.

However, there are many different technologies used for these modems, other than 3G or HSDPA, such as GPRS, the main difference from the user point of view being data transfer speed. Basically, the order of increasing speed is GPRS, 3G, HSDPA.

I have only just started to write this section (as at December 2010), based on my experience with three different 3G modems. I present some notes on these that you might find useful. I live in Australia, so these notes will be particularly useful for other Aussies.

if you live in Australia, this page is particularly useful. It has APN's for all the 3G vendors:
http://www.unlockguru.com/2011/06/australia-3g-apn-setting/

When PupDial is started and a new/changed modem is detected, PupDial tests that the modem responds and tries to determine a suitable "initialization string" -- these are commands that are sent to the modem, known as Hayes Commands. These are also used for analog modems, but with some extensions. This wikipedia page is a good introduction, and also outlines the 3G/GSM modem extensions:

http://en.wikipedia.org/wiki/Hayes_command_set

It may be that PupDial does not get the initialization string quite right for your modem. In that case, if you are able to find an alternate string that does work, let me know.

Here is various information that users have sent me, or that I have found:

Technical information

These are some notes for those who want to understand how Puppy is doing things "under the hood". Users don't need to know this stuff.

There are two types of modems, from the point of view of detection in Puppy: internal (fixed) or external (hotpluggable, or removable). The internal modems are detected when Puppy boots, the removable may be detected at bootup but also if the modem is plugged in after bootup.

At bootup, the script /etc/rc.d/rc.sysinit causes the correct drivers (modules) to load for detected hardware. If you look in rc.sysinit, you will see an important line of code: echo add > ${ONEPATH}/uevent #generates an 'add' uevent. This tells the kernel to generate what is called a 'uevent' for a detected item of hardware. There is a daemon program, 'udevd' that reads these uevents and in accordance with rules in /etc/udev/rules.d and /lib/udev/rules.d, causes the appropriate driver, firmware (etc.) to load/install.

The most important udev rules file is /etc/udev/rules.d/50-udev-puppy-basic.rules, which has these two lines in it:
# kernel firmware loader
SUBSYSTEM=="firmware", ACTION=="add", RUN+="/sbin/pup_event_backend_firmware"
# Module autoloading
ACTION=="add", SUBSYSTEM=="?*", ENV{MODALIAS}=="?*", RUN+="/sbin/pup_event_backend_modprobe" The two scripts 'pup_event_backend_firmware' and 'pup_event_backend_modprobe' take care of driver and firmware loading. Firmware are data files needed by some drivers, and these are kept in /lib/firmware.

All of Puppy's hardware detection and module loading is developed especially for Puppy and is different from all other Linux distributions. The firmware also (plus any other data files or executables) required by a driver, may not initially be in /lib/firmware, but in a 'firmware tarball' kept in /lib/modules/all-firmware -- pup_event_backend_modprobe takes care of expanding the appropriate firmware tarballs.

An important point to note is that wireless modems are often hybrid, or dual-personality devices. My 3G USB modems have two personalites -- they can behave either as a storage device or a modem. In most cases, when first plugged in, they are in storage mode and will not work as a modem. They have to be switched to modem-mode, and we have a software program called 'usb-modeswitch' to do that...