See Dlink_DWL900AP+ for general info.

This article is a copy of: http://www.ralphfowler.com/links/dwl900.html

By: Ralph Fowler, N4NEQ

3/16/03: Please visit this page in a day or so. I have completed lots more mods and tests and need to add them to the page.

Originally written 11/24/2002

Revised 11/25/2002, 1/13/2003, 3/14/03

Please see the new comments (3/14 and 3/15) concerning potential serial port and JTAG port hackability as well as additional details of my testing.

I just took apart and analyzed a D-Link DWL-900AP+

This is one of the new so-called 22MBb access points. Originally costing $119.00 at Micro Center, they have been seen on the web for as low as $85.00.

There's also an occasional rebate

D-Link Manufacturer's data is located at: http://www.dlink.com/products/digitalHome/wireless/11b+/dwl900ap+/

This unit can:

Its repeater and client modes open some INTERESTING possibilities! All it needs to know is the remote unit's MAC address.

There's a site survey mode- just turn it on and it detects other networks. Select the other network you want to access from a menu. It even automatically sets your SSID to that of the other network

According to D-Link, the repeater mode is not "supported", because it isn't part of the WiFi certification. They claim that it (and the client mode) only work with certain other D-Link units. I know that not to be true! Please note that the repeater mode did not appear on the DWL900AP+ menu until after I had updated firmware to Version 2.2 (available on the D-Link website).

One major downer: The site survey mode (and the AP itself) have no feedback to show the quantity/quality of signal from the other systems. A little graph or at least a number would br great. The log page does show associations and disassociations, though.

Other Interesting Features:

Has PC card inside with 2 antenna ports that are VERY EASY to solder right to! There are also 2 sets of pads that can accept a chassis mount SMA female. Selecting between these and the solder pads that are currently used is done with the move of a pair of chip capacitors. The card uses the new TI ACX100 chip. It is the same chip used in the DlinkDwl650Plus card.

Revised Dec 9, 2002: Check out the hidden weca.htm page in the web interface. It allows power setting as well as the selection of how the antennas are used.

Revised Jan 13, 2003: With the January 3rd release of firmware release 2.5, the Antenna selection and Power selection (up to 19 dBm now!) are now on the web page configuration pages. There are several other additions, as well as an alleged fix to the SNMP security bug. Its also reported that association to non-Dlink access points is more reliable. The hidden weca.htm page appears to now be gone.

UPDATE 3/14/03

My Testing

Here is what I have done with the unit so far:

I happen to have one of the Atlanta Freenet nodes near my home. The backbone nodes are currently using Cisco 340 Bridges (could havbe used APs but this is what we had). I used the site survey mode on the Dlink to acquire the Cisco and set it up as a repeater. The DLINK took on the ESSID of ATLANTAFREENET.ORG and repeaterd it over the local area, allowing laptop users to associate and surf.

Next, I got another DWL-900AP+ and put it in a place where it could hear the first one (but not the Atlanta Freenet node). Using site surver, I acquired the signal from the other Dlink and began repeating it. Again, laptop users were able to browse and surf.

A friend brought his Linksys router over and we were able to succesfully repeat it with the Dlink as well. I'm sorry tbut I don't have the model and firmware release of the router handy.

INSIDE THE DWL-900AP+

The Silicon:

Power is regulated by AIC1563CN Supply voltage: 30V; versatile DC/DC converter. Specs say it takes 3-30 volts in 1.5 amp out with no heat sink

http://doc.analog.com.tw/ap_note_pdf/an004.pdf

Lastly, there is a chip with the part # AB!5C0230 that I cannot identify. I may have misread the number. It is small surface mount device and reminds me of a PIC.

External connections:

There is a gas tube protector across the power.

Power over Ethernet??? It looks like this may be fairly easy to do Interesting thing about this ethernet jack: pins 4-5 and 7-8 are internally bridged. This is the New York City Wireless POE standard. (4-5 Pos 7-8 Negative) In tracing these connections through the access point it appears that, they get connected together through 2 resistors and then disappear under a chip. This may have been done to protect the power supply of an accidentally connected POE source. I wouldn't put power on these pins directly without further testing. I did notice a missing capacitor- think it was C53. It is across the power leads.

I think that if I were to experiment with powering over ethernet, I'd remove the 2 small chip resistors and then come from pins 4 and 7 on the Ethernet jack over to these 2 pins. I'd use a voltmeter to verify which of the capacitor pads was positive, and then connect the 2 ethernet pins over to the proper pads making sure to observe polarity. If you try this and damage something, it is your problem- so please don't try unless you have figured it our or you are willing to make the sacrifice!

I see many interesting possibilities, and I'd love to see someone hack further on one of these units.

UPDATE 3/15/03

Jan Peman from Sweden writes to say that he has figured out JP2 (the 14 pin connector). He says it appears to be a JTAG connector and that the pinout shows it to be a standard iCARD from iSYSTEM (not TI). Jan also believes that the 8 pin connector (J3 beneath the pcmcia connector) might be beginnings of a serial port, but that he hasn't yet been able to check it out. Thanks Jan for that info, and anyone else has anything to add- please let me know Here are the photos:

DlinkDwl900Ap+ (last edited 2008-04-13 16:34:00 by localhost)