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They also crucially provide center taps to provide a path for DC currents from the transmitter to ground and to give the receive signal the correct common mode level. Also because of the aforementioned center taps the pinouts of a jack with integrated magnetics will almost certainly differer from a plain jack.

http://www.smsc.com/media/Downloads_Public/lan9000/9512_sch.pdf

(that is a reference design for the lan chip the Pi guys are using)

So without the correct magnetics things are unlikely to work at all.

According to the present wiki information Model A received "Onboard Network: None".

Neither model precludes a USB wifi dongle(and some stuff, particularly some RaLink, actually works); but it looks like the default options are either "None" or "10/100 ethernet provided by a SMSC9512 USB hub/Ethernet controller hanging off the SoC's USB master port.

A case design allowing for a USB dongle to be installed; but protected inside the case, should be trivial enough; but is not default.

Have you noticed a distinct lack of USB 5.25" drives? I'm fine with a wall wart for power, but nobody even makes a USB floppy controller chip that recognizes 360k as a valid format. (There's one that'll do 1.2MB, but not 360k.)

I've been encouraging Jens Schoenfeld to make a USB Catweasel controller for those of us without PCI slots. I suppose it's probably easier to put PCI slots on a laptop, though.

Perhaps I'm just in it for the absurdity factor.

They stopped them because of the slow datarate. Todays when a photo (even compressed) takes ~800 KBytes and an MP3 ~4 MBytes, would take a while to send it to the notebook using IrDA. 100Mbit (as advertised) would be enough for thoose applications. I think if such technology would be available at equivalent or even lower price than Bluetooth a lot of manufacturers would "buy it".

BTW! There are some chipmakers which are still considering IrDA:
http://www.smsc.com/whatsnew/pr/usb2230pr.html

Not only did LANceGS cost too much ($150 plus drop shipment from Germany), but it also seems the developer refused to release any specifications for a long time -- even the photos on the website had the markings on the Ethernet chip ground off. (It's since been revealed that it uses an SMSC LAN91C96, and the latest release of Contiki supports it just fine.)

-lee

I was pretty disappointed. There were tons of solder bridges (where the solder connects two pins together), some pins that didn't stick reliably, etc. I wound up spending as much effor cleaning up as I would have doing it by hand in the first place. If I was going to try it again, I might make a solder mask to apply the paste only on the pads, instead of running a thin line across the pads as they recommended.

The answer lies in the datasheets. Many RTC chips have more than 128 bytes of NVRAM, and use a bank swapping technique to select the alternate banks. Dallas Semiconductor is one such source, although most new systems have the RTC embedded in one of the main ICs of the chipset or on the super IO chip. Here is one example, the SMC FDC37N958FR, which is used in the Dauphin Orasis v1, an SBC I am experimenting with putting LinuxBIOS on to get around certain limitations. Page 215 is the start of the RTC/NVRAM access. This particular device has 256 bytes of NVRAM, several of which are reserved for the RTC and 8051 scratchpad. Since there is only 256 bytes, there is no bank switching. The DS1251 is an RTC/NVRAM chip with 512KB of static RAM. The little bitch is expensive, too. :-) It uses a banking method where one of the normally user-available registers is now a bank selection register.

I seriously doubt many systems have more than 256 bytes of NVRAM. That is a LOT of space for settings.