Last week, Apple and Nokia got into a very public dust-up over the future of the SIM card — a staple in phones all around the world — thanks to a Financial Times article pointing out that the two had filed competing proposals with the European Telecommunications Standards Institute (ETSI) for the so-called "fourth form factor (4FF) UICC," more commonly known as the "nano-SIM." The nano-SIM proposals seek to standardize a new SIM card that would be even smaller than the current micro-SIM popularized by the iPhone, freeing precious extra millimeters inside the phone's chassis for more circuitry, more battery capacity, and slimmer profiles.

We've now had a chance to see the original proposals for the nano-SIM standard from Apple, Nokia, and RIM, and we have a better idea on what the ETSI will be voting on later this week.

Perhaps somewhat surprisingly, Apple appears to have the most conventional proposal:

4ff-apple

Apple suggests that the nano-SIM should effectively be a micro-SIM stripped of virtually all its plastic. This is the card that the::unwired had a chance to see back at Mobile World Congress from Giesecke & Devrient, the firm that debuted the first commercial SIM two decades prior. Another SIM provider, Oberthur Technologies, is prototyping examples of Apple's card as we speak (pictured below, set inside the outline of a standard 2FF SIM for comparison).

Oberthur-4ff

In soliciting proposals for the nano-SIM standard, the ETSI has said that the new card must support eight electrical contacts — as current SIMs do — but it doesn't specify the layout or configuration of those contacts. Apple maintains the old configuration; in other words, with an adapter, you could theoretically use their nano-SIM in a micro-SIM or mini-SIM phone sold today. Nokia and RIM take a very different approach:

4ff-nokia-rim

The 4FF proposals from Apple's competitors look more like microSD cards than present-day SIMs, which would presumably make it difficult or impossible to use an adapter to get them working with older phones. Nokia points out that its proposal wouldn't require a tray or other SIM carrier — in all likelihood, that means that the Nokia design has notches that would allow it to be held in place in a slot. The Apple proposal, being stripped of all plastic surrounding the contacts, requires some external holder to keep it in place.

Another ETSI requirement for the 4FF standard reads:

The design of the fourth UICC form factor shall prevent the 4FF from becoming jammed in a Mini-UICC reader. An example is that if the 4FF is turned 90 degrees and it fits perfectly into the Mini-UICC reader (4FF length = Mini-UICC width).

Nokia contends that Apple's design violates that requirement, and it's easy to see why: its nano-SIM is roughly 12mm long while the existing micro-SIM is 12mm wide, giving users the opportunity to jam a nano-SIM sideways into a micro-SIM slot and get it hopelessly stuck. It's a scenario that the ETSI's documentation specifically calls out.

Apple's design is in many ways the least controversial

Notably, recent verbiage both from the Financial Times report and from Nokia itself group Nokia and RIM into the same camp, so it seems that the two giants (along with Motorola) have put aside their differences in an effort to fight Apple here — it's unclear whether the consortium is proposing Nokia's or RIM's original design, though it's a safe bet that Nokia threw its weight around in this relationship. Either way, it's a little surprising that Apple's design is in many ways the least controversial — it rocks the micro-SIM boat as little as possible, whereas Nokia is looking for a more thorough reboot of the now 20-year-old Subscriber Identity Module.

Which design will come out on top? The ETSI meets to decide later this week, and we'll be paying close attention.