Existing phone handsets for GSM/2G
Classic 2G-only GSM handsets were made from mid-1990s into early 2010s,
and they were made in all kinds of form factors: candybar, flip, slider
and all kinds of exotic variants.
They were made with screen sizes ranging from tiniest to huge, both
black&white and color, and with every possible input method: T9, QWERTY,
touch screen and even voice recognition.
Different models were made that catered to every desired set of functionality,
and every artistic taste one can think of.
Today's so-called dumbphones
for 4G and VoLTE are hideous beasts
in comparison — they pale in quality to traditional 2G phones.
However, from the perspective of an extreme Computer Science nerd
like Mother Mychaela of FreeCalypso, even those old and beautiful 2G phones
exhibit a severe flaw: they run closed-source firmware.
You see, every cellular phone handset, no matter how old, no matter how
dumb
and primitive
, is still an embedded microprocessor system,
and it still runs embedded software, also known as firmware.
The end user functionality of a phone, such as which button does what,
how the menu system is organized, what kind of data model is used for
storing contacts and SMS etc, all of these essential functions are
determined not by physical design and construction of
the phone as an artifact (electrical, mechanical etc), but by operation
of its embedded firmware.
It is really a little computer, controlled by software first and foremost.
The problem with absolutely all historical GSM/2G phone handsets is that their operational firmware is closed-source, meaning that its source code was held secret by phone manufacturers, and has by now almost certainly been completely lost. For every computer program, including embedded firmwares for devices such as phones, source code is the original form in which that program was written, and is the form of the program needed in order to study it and understand how it works, and to make changes to it. Having the source code withheld deprives users of the essential ability to truly understand how their phones work, to debug and troubleshoot problems, and to make functional improvements.
Absolutely every cellular phone handset I have ever used in my life has always exhibited some functional bugs or defects, even in the core functions of interfacing to the cell network and the SIM card, and the higher-level user functionality of every phone I've ever used has likewise always exhibited some design flaws I can easily point out. None of these problems was ever due to some physical defect in the phone — instead there is nothing wrong physically, but the functional bug or design flaw is always somewhere in the firmware. If I had access to the source code, I could fix those bugs myself and make my own improvements to the functionality of the phone — but the lack of source code makes those defects unfixable.
The goal of building a FreeCalypso phone handset
One of the primary objectives of FreeCalypso has always been to produce
our own GSM phone handset, aka dumbphone
, that would serve as a
replacement for the usual proprietary flock.
We have already accomplished many significant milestones toward this
goal:
Our FCDEV3B GSM MS (mobile station) successfully connects to GSM networks, makes and receives calls, sends and receives SMS — but because this board has no LCD or keypad UI elements, a host computer must be connected at all times for control.
Our Luna platform from 2020, originally put together using a historical iWOW DSK board and later switched out to Caramel2, adds a D-Sample-equivalent LCD and a 5x5 keypad to the standard Calypso core. This platform can operate untethered, without a host computer, but because it's a messy arrangement of multiple boards interconnected with ribbon cables, easy development is still hampered.
Our FC Tourmaline firmware runs on this Luna platform, and some forward progress has already been made with handset UI functionality, despite a very inconvenient development platform.
Our next planned step is to build our FC Venus development board,
conceived in 2021 and described in
this specification.
This FC Venus GSM MS board is envisioned as being very capable, a
mother of all boards
(as in GSM MS development boards) in a way,
and it will serve both as a stepping stone toward building a true FreeCalypso
Libre Dumbphone handset and as a very good engineering-oriented GSM MS
for GSM network development and testing.
2G and 4G support in the hypothetical new dumbphone
When I (Mother Mychaela) tell people that I seek to design and build
my own dumbphone
handset, they often ask why I am building it for
GSM/2G only, and not for 4G and VoLTE.
For a detailed answer to this question, please read about
inverted order of preference.