The Bifferboard is a very small Linux compatible computer designed and sold in the UK featuring a 486SX-compatible microcontroller @150MHz, 8MB Flash, 32MB RAM, Ethernet port, and either single or dual USB ports, making it ideal for networking, such as to control devices over the Internet, for example, while using little power.
I first came across the Bifferboard when I by chance saw an eBay listing in 2025 for the single USB port version with case for just £5 ($6.10), which I purchased, and later on I bought the dual USB port version with case from the same seller for £9 ($10.98). While the single port model was good value, the dual port version was especially worth the money as the seller included as extra a power supply (which also works on the single port version) and USB interface data cable (which works on both versions).
The original site for the Bifferboard has gone down:
Which I cannot find an archived version of.
It was then replaced with:
https://sites.google.com/site/bifferboard/
But that also is no longer available but it has been archived:
https://web.archive.org/web/20240222222644/https://sites.google.com/site/bifferboard/
However, you may want to look at an older version as the more recent copies aren't stable and there are issues loading the other pages.
There is also the Bifferboard wiki which appears to be a replacement for the old site:
It would seem the single port Bifferboard is no longer sold new unlike the dual port version, which makes sense as that is more versatile.
The Bifferboard consists of two PCBs plugged into each other, the top PCB which is the main part of the computer, and the bottom PCB, which is larger and provides power, interface and status lights. Starting with the smaller PCB, on the top side it has a 10-way male header J1 (JTAG, serial and power) with pin 7 missing (likely to help separate the JTAG pins from the serial pins). Pin 1 is determined by the square solder blob on the PCB underside. There is an unknown chip, likely flash memory, with a label having ‘00B3F606040D 07120600317’ written on it. There are many passive components, and in the corner of the PCB we find ‘G5A55042340’ printed. On the PCB underside side it has a IP101A LF Single port 10/100 Fast Ethernet Transceiver, what is likely the microcontroller under a heatsink, NT5SV16M16BS-75B 256Mb Synchronous DRAM, 25MHz oscillator, and some passive components. The PCB also has a 7-way male header J2, which plugs into the bottom PCB via 7-way female header J1, and 7-way male header J3, which plugs into the bottom PCB via 7-way female header J2.
On the top side of the bottom PCB there is an Ethernet connector, power in socket, yellow (link) and blue LEDs, push button, 7-way female header J1, USB-A female socket, 7-way female header J2, 6211A 1144/33 LDO 3.3V voltage regulator, H16102MCG Ethernet transformer module. ‘C5AFF022341’ is written above and to one side of J2. There are a few passive components on the PCB underside, and a RoHS COMPLIANT mark 2002/95/EC, so the earliest the board was from is 2003 since that's when it came in affect in the EU.
Included with the the dual port version (see the relevant section on this page for more information about that version) I bought was a power supply, model SAW-0501200, rated 5VDC 1200mA, centre positive, this is handy to have as both Bifferboard versions use a not very common small barrel jack connector for power. I measured the power supply voltage unloaded and got 5.43V, which was a good sign.
Additionally, a USB interface data cable was also given with the dual port Bifferboard, which can be used on both versions and is a UART to serial converter cable with a small plastic box in between. The interface cable has a USB connector on one end, a 5-way female block connector the other end which plugs into the Bifferboard header pins, and an unlabelled 2-way switch in the small plastic box part.
It looks just like this:
https://omnima.co.uk/store/catalog/USB-to-UART-adapter-p-16145.html
However, that one has a 4x2 female header block and looks like it doesn't have the switch so perhaps it's an updated version. I did find a page with a 'console cable' for the Bifferboard but there was no picture.
Going back to the interface cable I have, opening up the box part (the two pieces are clipped together) reveals a generic module using a Chip On Board (COB) with the module soldered to a larger PCB featuring the switch. I don't know the purpose of the switch, it's possibly for voltage selection, I left it in the position it arrived in (away from the USB end).
The non-USB part of the interface cable only has three wires connected to the 5-way female block, coloured red (pin 1, indicated by the arrow on the connector), white (pin 3), and blue (pin 4). I worked out the pinout to be:
1. (red) GND
3. (white) TX
4. (blue) RX
I plugged the interface cable into my Windows 11 laptop, in Device Manager it showed 'PL2303HXA PHASED OUT SINCE 2012. PLEASE CONTACT YOUR SUPPLIER.' Although I had other serial adapters I could use I wanted to get the supplied interface cable working as it would save me a bit of trouble by having the right connector for the Bifferboard. I found this solution:
Which worked for me.
Since the Bifferboard doesn't have a video output, its on-board serial connection is the means by which we view its output and communicate with it.
For connecting to the serial port we can see the pinout in section 'CPU J1 JTAG/Console' of the following site:
https://github.com/bifferos/bb/wiki/Pinouts
On my Bifferboard there are male headers already soldered, pin 1 on the power connector end.
I used the interface cable, which can be plugged directly into the Bifferboard header using pins 6 - 10, red wire on pin 6. After plugging the interface cable into my computer I opened a serial connection set to 115200 in PuTTY, plugged power into the Bifferboard, and immediately got boot messages. Oddly, the power LED wasn't on.
I've reproduced some of the interesting messages as follows:
BIFFBOOT v3.11 Community Edition 00B3F606040D 32-bit Loader by bifferos (c) 2013
Linux version 2.6.37.6-biff (smh@att-desktop) (gcc version 4.3.6 (Buildroot 2011.11) ) #39 Sat Aug 28 17:20:53 BST 2021
Early serial console at I/O port 0x3f8 (options '115200')
32MB LOWMEM available.
Initializing CPU#0
Memory: 30100k/32768k available (1052k kernel code, 2216k reserved, 338k data, 376k init, 0k highmem)
CPU: Cyrix Cx486SLC
No coprocessor found and no math emulation present.
BusyBox v1.22.1 (2020-04-29 14:06:47 GMT) multi-call binary.
We also get reported:
* Setting hostname...
* Starting telnetd...
* Starting inetd...
* Setting up GPIO on button pin
* Starting doorbell monitor
Starting button monitor service
Then it drops into the command prompt.
It took about 23 seconds from plugging power into the Bifferboard to reaching the command prompt. When I powered the Bifferboard with an Ethernet cable plugged in from my router I got this information during boot::
NIC up in: 1180ms
Link up
Checking NIC
Since I got boot messages, and clearly it's running Linux, either the Bifferboard was shipped with an O/S preinstalled or the previous owner installed the O/S. Either way, since there is a date of 2021 it's a fairly recent version of Linux and may be this:
https://github.com/bifferos/bb
At the command prompt you can use the help command to get a list of commands, however, there are additional commands not listed, such as ls.
I found the df command didn't give any useful information and the free command didn't work, however:
cat /proc/meminfo
Reported MemTotal 30476 kB, MemFree 26544 kB, which matches the claimed 32MB RAM.
cat /proc/partitions returned 'No such file or directory'.
We can get information about the CPU using:
cat /proc/cpuinfo
I've included some of that information below:
vendor_id : CyrixInstead
cpu family : 4
model : 1
model name : Cx486SLC
fdiv_bug : yes
bogomips : 49.15
address sizes : 32 bits
To get the Bifferboard online we simply need to connect an Ethernet cable to the Ethernet port with the other end connected to a router or switch, when the Bifferboard is powered the yellow LED will light to show network activity.
To get the hostname we can use the hostname command, which returned doorbell. To get the IP address we can use ifconfig and doing so I was able to ping the Bifferboard from my laptop connected to the same network using the IP address but not when using the hostname. I wasn't able to SSH using the hostname and putting the IP address into a browser didn't do anything.
Please note: it is advisable to have read the 'Single USB port version' section first.
I found the dual port version being sold here:
https://omnima.co.uk/store/catalog/Bifferboard-Dual-USB-port-p-16194.html
Unfortunately there is no image. We can see that the sale price is £45 ($55.99), a lot more than what I paid. The site specifies the following details:
150MHz CPU, Intel 486SX instruction set, MMU.
1 watt power consumption (200mA @5v)
68mm x 28mm x 21mm (weight 28g)
32MB SDRAM/8MB Flash
OHCI/EHCI USB 2.0
10/100 ethernet
Serial console 115200 baud (can be used as 2 GPIO)
4-pin JTAG (can be used as GPIO)
2 permanent GPIO (1 LED, 1 button)
Linux 2.6.37.6
Supplied pre-flashed with OpenWrt
I have found one page dedicated to the dual port version involving using it in a project:
https://www.aslak.net/index.php/2012/04/29/wlan-phone-operated-tank-with-webcam-hardware/
It has a photo of the Bifferboard in what appears to be the same (half piece) case that I have and there is a link above it to the original site so it would seem it was sold with the case. The link is down but there is an archived version:
https://web.archive.org/web/20111202182254/http://bifferos.co.uk/buy/000014.html
No picture but the same £45 price, and of the very little information it should be noted:
"The SD/MMC card reader cannot be used at the same time as the second USB port.
The power jack is the same size as on the single-port version, so the same power supply can be used, although the 1.2Amps output current is not quite sufficient for two full-power USB 2.0 devices."
The dual port version is over double the size of the single port version and came in a plastic case made of two pieces. The bottom piece features a cut out for the two USB ports (labelled as 'USB Printer' and 'USB Storage') along one of the short ends, as well as an SD card slot ('SD/MS'), a hole for the LED ('*F/card') along one of the long ends, a hole for power ('5V DC IN'), reset button ('Reset'), ethernet ('LAN'), along the other short end. Although the USB ports are labelled as 'USB Printer' and 'USB Storage' there is no reason why you can't use other USB devices.
Like the single port version, two PCBs make up the dual port Bifferboard, the top PCB is the 'brains' and plugs into the bottom PCB, which is bigger, and contains the main interfaces, power connector and status LED. On the top side of the smaller PCB is a 6-way male header J1 (JTAG - pin 1 is indicated with an arrow on the PCB), and a 5-way male header J2 (serial interface) having pin 2 missing. Also on the PCB is likely a flash memory chip with a label printed with ‘00B3F6008CF2 0511051605F9’ on it, IP101A LF Single port 10/100 Fast Ethernet Transceiver, 25MHz oscillator, many miscellaneous minor components, and a label with ‘IO63’ written on it.
On the underside of the PCB it has the sequence ‘65A56042440’ printed, and there is a NT5SV16M16BS-75B 256Mb Synchronous DRAM, possibly the microcontroller under a heatsink, and a number of smaller components. There is also a 10-way male header JP1 which plugs into JP2 of the bottom board, and a 10-way male header JP2 which plugs into JP1 bottom board. Note that these four headers that connect the two boards together are of a much smaller size than on the single port Bifferboard.
On the top side of the bottom PCB there are two female USB-A sockets, two 10-way female headers JP1 and JP2, Ethernet socket, reset push button, power socket, yellow LED, and SD card socket. Also, the PCB is home to a H16102MCG Ethernet transformer module, GL827L USB 2.0 Single Slot SD/MMC/MS card reader controller, 6120E A6322 (possibly a voltage regulator), and YJE CZYJX unknown chip.
A single screw holds the larger PCB to bottom piece of the case, however, I was unable to get the PCB out even with the use of a spudger so I am unable to document what is on the PCB underside.
To test I used the USB interface data cable I spoke about in the single USB port Bifferboard section, the dual USB Bifferboard version has two male interface headers, one 5-way (J2), the other 6-way (J1). The USB interface cable needs to be plugged into J2 so that pin 1 (red) connects to the isolated pin on the 5-way header of the Bifferboard (connection 2 doesn't actually have a pin).
After plugging the interface cable into my laptop I opened a serial connection in PuTTY set to 115200, then I plugged power into the Bifferboard, the blue power LED (D2 ) was on, and immediately I got boot messages. From power on it took about 25 seconds for the ‘Please press Enter to activate this console.’ message to appear, then more boot messages appear. Even if you press enter when prompted it’ll continue to boot, so you will need to press enter again to access the command line.
I have repeated some of the interesting boot messages here:
BIFFBOOT v3.3 00B3F6008CF2 32-bit Loader by bifferos (c) 2010
Booting Linux with:
Linux version 2.6.32.20 (biff@fonzi) (gcc version 4.1.2) #5 Mon Feb 7 23:21:40 GMT 2011
Early serial console at I/O port 0x3f8 (options '115200')
bootconsole [uart0] enabled
32MB LOWMEM available.
Memory: 30192k/32768k available (1298k kernel code, 2184k reserved, 352k data, 116k init, 0k highmem)
CPU: RDC R3210/R3211
Please be patient, while OpenWrt loads ...
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
gpio-buttons driver version 0.1.2
input: gpio-buttons as /devices/platform/gpio-buttons/input/input0
We can see that the Bifferboard already has an O/S installed on it (OpenWrt), but is running an older release than the single port version I have, we also see that both USB ports have been detected.
You can press any key to enter the command line and will be greeted with:
BusyBox v1.17.2 (2011-02-06 12:53:15 GMT) built-in shell (ash)
Enter 'help' for a list of built-in commands.
Along with OpenWrt ASCII art and root command prompt.
Using the command will indeed give you the available commands but there are additional ones not listed, such as ls, which can also be used.
This isn't actually all the commands, for example, ls works.
df-h returns 6.9M size, 2.8M used, 4.2M available. Which agrees with the stated 8MB flash.
free gives information about free RAM, which returns 30308 total mem, 20668 free. This agrees with the stated 32MB RAM.
We can also use:
cat /proc/meminfo
To get more detailed information.
You can use:
cat /proc/cpuinfo
To get CPU specifics. We can see vendor_id is RDC, CPU family is 4 (i.e. 486), model name is R3210/R3211, no FPU, bogomips 49.02, and 32 bit address size.
We can list disk partitions with:
cat /proc/partitions
We can see there are three partitions.
With an Ethernet cable from a router/switch plugged in to the Bifferboard's Ethernet port we can get it online, the D1 yellow LED will light to show network activity. I found that the hostname command wasn't available but ifconfig gave the IP address and I was able to ping the IP address from my laptop that was connected to the same network. I could SSH using the IP address on port 22 using PuTTY, and putting the IP address into a browser took me to the OpenWrt log in page.
All content of this and related pages is copyright (c) James S. 2025