Frequently asked questions/Wifi

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Customers using Gumstix OpenEmbedded should go to gumstix.net and the related user wiki

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For customers using buildroot:


If your question is not in this FAQ, please feel free to ask it on the Mailing list

Contents

Can the 802.11 B/G (wifi) module from wifistix or wifistix-CF be used on the netmicro-SD?

Yes, the wifi module can be removed from a wifistix or wifistix-CF expansion board and then connected on to the netmicro-SD-vx board.

This change results in a netwifi-microSD-vx expansion board.


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What's the socket that the DRCM81-FCC (wifi) module plugs into on the netmicro-SD board?

The socket is available at Digikey:

  • Molex Part# 54722-0507
  • Digikey ID# WM24033-ND


Gumstix does not sell this socket. Check the schematics section for further information:


.

Does the CF port on wifistix use one of the UARTs? If so, which one?

The wifi module is actually sitting on a CF "bus", and the additional CF slot does not therefore use any extra lines relative to wifi-only.

How does a gumstix connect to a network?

There are several ways to connect to a network:

  1. Obtain 10/100 Ethernet using a connex motherboard with either an etherstix expansion board or any netstix expansion card. the netstix FAQ tells how to get an ethernet connection started for a new netstix configuration.
  2. 802.11(b) or 802.11(g) WLAN using the connex motherboard with a wifistix expansion card. wifistix can be operated at 54 M bps.
  3. 802.11(b) or 802.11(g) WLAN using a CompactFlash WiFi card plugged into a expansion card that has a CF socket (netCF or CFstix). (The only one with which we've really done any testing is the Netgear MA701 in a cfstix expansion board).
  4. 802.11(b) or 802.11(g) WLAN using a USB wifi dongle plugged into breakout-vx or console-vx expansion board plugged into a verdex motherboard. See Template:FAQ/Questions/USB-wifi-dongle.
  5. Bluetooth(TM) wireless via a Bluetooth option on either a basix or connex motherboard.
  6. USBnet via any usb port
  7. Serial connectivity via a waysmall, or tweener, expansion board with a serial null-modem cable. gumstix Linux includes a complete TCP/IP stack, and a fully functional PPPd, which will allow a network connection to be establishd over any of the serial port.

Can wifistix operate in ad-hoc or managed mode?

Yes, wifistix can operate in ad-hoc or managed mode.

Can the gumstix become a wifi access point or it is just a device on a wifi network?

This will depend on what method you use for wifi access. Any device which supports (and is using) the hostap drivers should work. Note that the wifistix does not support the hostap drivers.

In order to configure the device as an access point change the following in /etc/pcmcia/wireless.opts from: 

  case "$ADDRESS" in
  *,*,*,*)
     INFO="Any ESSID"
     ESSID="any"
     ;;
  esac


to: 

  case "$ADDRESS" in
  *,*,*,*)
     INFO="Any ESSID"
     ESSID="gumstix"
     MODE="master"
     ;;
  esac


Wifistix

The wifistix does not support running as an Access Point (AP) at this time.

Other options

The gumstix software provides the necessary software support to become an AP (wireless Access Point) when using the connex motherboard with a WiFi card, like the netgear ma701, in either a cfstix or netCF expansion board. Wifi cards like this netgear card support AP mode (through the hostap driver) unlike the wifistix expansion board which does not support the hostap driver.

Which WiFi adapter cards do the cfstix and netCF expansion boards support?

http://linux-wless.passys.nl/ where you choose "CF" as interface and it returns http://linux-wless.passys.nl/query_hostif.php?hostif=CF list. The cfstix and netCF expansion boards should support a wide range of compact flash cards.

- a Netgear MA701 compact flash card for WiFi. This netgear card is available via Amazon dot com.

- The SMC 2632W

- the Ambicom WL1100C-CF card which is 802.11b works fine - edit the init.d file and comment out mmc stuff to enable CF and it should dhcp just fine. (Beware! Newer AmbiCom WL1100C WiFi cards do not seem to work at all, or poorly at best, even with the patch suggested in the Mailing list by Michael Taylor! [1])

- A Belkin F5D6060? - from TigerDirect for $20.

Tiger Direct

- A Pretec CompactWLAN 802.11b card. You have to enable the compact flash stuff as with other cards. You have to add the following to /etc/hostap_cs.conf if you want to use it with the hostap driver. 

   card "Pretec WLAN"
      version "Pretec", "CompactWLAN Card 802.11b", "2.5"
      manfid 0x0156, 0x0002
      bind "hostap_cs"

Are drivers available for the wifistix board?

Buildroot versions pre-1066

In the HEAD of buildroot, there's a "wifistix" package in the buildroot config. Turn that on but leave all the pcmcia stuff the way it is.

Adding the wifistix package will build the driver and modify /etc/network/interfaces as needed.

Only other change is to modify /etc/modules to turn off MMC and turn on CF.

Builroot versions post-1066

Starting in the r1066 release of the rootfs, the wifistix drivers are included by default, and /etc/modules defaults to loading CF not MMC. So on these more recent filesystem images, wifistix will work out-of-the-box.

Which module is in wifistix?

wifistix and wifistix-cf use the DRCM81 module from Wistron NeWeb Corporation with the Marvell® 88W8385 chipset.

Which antenna connector does wifistix use?

The wifistix expansion board uses a Hirose U.FL ultra-miniature coaxial receptacle connector on the WiFi module.

The WiFi module's U.FL connector is compatible with a family of pre-assembled Hirose coaxial cable products and the WiFi antenna sold by gumstix. U.FL-compatible cable assemblies, adapters, accessories and 2.4GHz antenna assemblies can be found at Digi-Key, by searching on the product term "U.FL". Synergy Systems, LLC carries U.FL to SMA and FME adapter cables (specified by Synergy for GSM applications, but the cables cover the 2.4GHz ISM WiFi band).

If you will be frequently connecting and disconnecting the WiFi antenna, it is recommended that you use a Hirose removal tool to disconnect the antenna/cable from the WiFi module, since prying at the connectors with a screwdriver and/or yanking on the cable can damage the assembly(s).

Is 802.11(a), (b) or (g) wireless networking available?

Yes, 802.11(b) or (g) WLAN networking may be achieved using a connex motherboard with a wifistix expansion board.

Click here for product information on the wifistix expansion board.

What are the FCC requirements around use of the wifistix products?

Federal Communication Commission Interference Statement

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following measures: 1. Reorient or relocate the receiving antenna. 2. Increase the separation between the equipment and receiver. 3. Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. 4. Consult the dealer or an experienced radio/TV technician for help. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: 1. This device may not cause harmful interference, and 2. This device must accept any interference received, including interference that may cause undesired operation.

Information

To assure continued compliance, (example - use only shielded interface cables when connecting to computer or peripheral devices) any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate this equipment.

IMPORTANT NOTE

FCC Radiation Exposure Statement

This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with minimum distance 20cm between the radiator & your body. This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter.

For OEM integrators

This device is intended only for OEM integrators under the following conditions: 1) The antenna must be installed such that 20 cm is maintained between the antenna and users, and 2) The transmitter module may not be co-located with any other transmitter or antenna. As long as the 2 conditions above are met, further transmitter testing will not be required. However, the OEM integrator is still responsible for testing their end-product for any additional compliance requirements required with this module installed (for example, digital device emissions, PC peripheral requirements, etc.). IMPORTANT NOTE: In the event that these conditions can not be met (for example certain laptop configurations or co-location with another transmitter), then the FCC authorization is no longer considered valid and the FCC ID can not be used on the final product. In these circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a separate FCC authorization.

End Product Labeling

This transmitter module is authorized only for use in devices where the antenna may be installed such that 20 cm may be maintained between the antenna and users (for example Notebook PC, access points, routers, wireless ASDL modems, and similar equipment). The final end product must be labeled in a visible area with the following: "Contains TX FCC ID: NKRDRCM".

Manual Information That Must be Included

The users manual for end users must include the following information in a prominent location "IMPORTANT NOTE: To comply with FCC RF exposure compliance requirements, the antenna used for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter."

Additional Information That Must be Provided to OEM Integrators

The end user should NOT be provided any instructions on how to remove or install the device. The module is for OEM installation only and can not be sold to end user directly.

Can a connex motherboard with Bluetooth(TM) be used with 802.11(b)/(g) wireless?

Using Bluetooth on a connex motherboard with 802.11(b)/(g) on a wifistix expansion board works physically but gumstix engineering has not tested this combination for interference.

Can a gumstix motherboard use both a GPS reciever and a 802.11(b)/(g) wireless? =

The (60-pin) GPSstix and the (92-pin) wifistix expansion boards will both mechanically plug into a connex motherboard ... interference ?

Would one of the alternate ways to connect Wifi and GPS work better ?

When should a 4v power supply be used? When should the 5v supply be used?

For any configuration that includes the netDUO-mmc expansion board, use a 4v power adapter.

For configurations including USB host power, a 5v power adapter should be used.

For all other configurations, either a 4v or 5v power adapter may be used.


.

How can extra flash storage, as well as having a A, B or G wifi conection?

Use a wifistix-cf expansion board that also has the 802.11(b)/802.11(g) capable wifi function as well as a compact flash slot - not yet announced.

Why is the CF adapter on the same side as the RJ45 jack on the netCF expansion board whereas the MMC adapter is on the opposite side to the RJ45 adapter on the netMMC expansion board?

Because the components and the boards "fit better" in each case-- actually much better-- and it is a function of the height of mmc connector vs the height of the cf connector.

Does the cfstix expansion board work with CompactFlash WiFi cards other than the Netgear MA701?

Yes, any CF card for which there is a linux driver ought to work fine — so if you can find a compact flash 802.11g card which has linux drivers, then you should be fine, assuming those drivers are provided in source code form, so they can be compiled for the ARM processor — this generally will be the case since mobile devices which are the ones that tend to use the CF interface, are often built on an ARM processor.

The only one with which we've really done any testing is the Netgear MA701 (which also happens to be nicely inexpensive).

What are the intructions for turning on the netgear wireless card?

Some of the netgear cards don't have up-to-date firmware on them. So they work but they don't function as well as possible. Luckily, the linux hostap driver comes with the ability to reflash the firmware on these cards. The instructions are here.

Everything's in the buildroot to do this reflash; patch the header file manually in the linux source tree to turn on the "let me flash firmware" stuff. It may just involve uncommenting one #define line or something from memory. Then upgrade with the latest firmware that is linked from that page above.

With or without the firmware flashing, plug the wifi card into a factory-image gumstix+cfstix and it should just work. Use "iwconfig" to associate with your AP.

battery operation

A wifistix + gumstix motherboard typically pulls ____ mA current ( ____ mW power) from the power supply while actively transmitting.

A Wifi CF card + cfstix or netCF expansion board + gumstix motherboard typically pulls ____ mA current ( ____ mW power) from the power supply while actively transmitting.

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