On Fri, 02 May 2008 20:27:34 -0700, windsurferLA <ps144nyc@yahoo.com>
wrote:

>Ethernet linked access point appears sensitive to cable length well
>below specified limits.

Appearances are often deceiving.

>I’m seeking to locate a wireless access point remote from my main
>router, a D-Link DI-524 whose wireless function has been turned off.

The DI-524 is not the best router on the planet. I think I have about
3 of them in the office, that have been pulled from service due to
range problems. They're also only 802.11b and are therefore slow. If
you don't need the wireless, there are many better routers available
for literally a few dollars.

>The
>wireless access point is being implemented with a nearly identical
>D-Link DI-524 wireless router whose DHCP function has been turned off.

No problem. I use wireless routers as access points all the time.

>The IP address of the second D-Link DI-524 wireless router has been
>altered so as not to conflict with the IP address of the first router.

Good.

>One of the LAN outputs of the first router is connected to one of the
>LAN outputs of the second router so that it acts like a switch.

Can I presume that you used a cross-over ethernet cable between the
LAN ports on the two DI-524 routers?

>I have tested the above configuration at three locations linked by three
>different CAT5 cables.

Commercial CAT5 cables or home made? I recently found an entire
building, where all the CAT5 wiring was to some odd specification,
which was totally useless for ethernet because it effectively split
one of the pairs of wires. I'm currently negotiating on the price of
replacing the connetors and reterminating about 50 wall jacks.

>Location #1 – WORKS fine when linked by commercially constructed 10’
>long CAT5 cable.

OK. That's your sanity check. Commercial cables are usually (not
always) known good. Is this a cross-over ethernet cable? Note that
LAN to LAN port connections must have a cross-over cable unless ONE of
your boxes has autoconfiguring ports. The DI-524 does NOT have port
auto-configuration and the cables must be cross over.

>Location #2 – WORKS fine when linked by home built 40’ long CAT5 cable.
>
>Location #3 – DOES NOT WORK when linked by home built 100’ long CAT5
>cable. – Not only is there no communication over the link, but the
>lights on both routers do not even indicate a connection. YET, if at
>this same location #3, the 100’ long cable is plugged into any one of
>several computers, the connection indicator lights come on immediately,
>and full normal network access is quickly obtained.

Wrong type of cable. It needs to be a cross over ethernet cable.
<http://en.wikipedia.org/wiki/Ethernet_crossover_cable>
I use the gigabit wiring scheme, where all 4 pairs are crossed over.

>As the cable length is well under the 100 meter (300 feet) maximum
>length for Ethernet, at first I thought that maybe the third cable is
>somehow wired differently, perhaps as a “Cross over cable” rather than
>as a “straight through” cable.

You're not adjusting the cable length. What you're doing is switching
cables, some of which are apparently straight through cables.

>I understand that some interfaces can
>cross and un-cross a cable automatically as needed. I am uncertain
>whether or not the LAN ports of the DI-524 have that feature, but an
>examination of all of my cables, both home made and commercially
>assembled, and all appear to be wired “straight through.”

Most commercial cables are straight through. I don't like to stock
two different wiring configurations. What I use is a home made cross
over adapter. It's an RJ-45 wall jack, with a short CAT5 pigtail to
an RJ-45 plug. The jack is wired normally, but the RJ-45 plug is
wired for cross over. When I need a cross over cable, instead of
destroying a perfectly good straight through molded commercial cable,
I use the adapter. I think you can also buy ethernet cross over
adapters on the web somewhere, but I'm too lazy to look.

>I’ve also sought to confirm that the problem is not associated with the
>RJ45 connector at the end of the cable. The symptoms are unchanged when
>a short (10 foot long) Ethernet extender (female to male) cable is used,
>so the connector at the end of the 100’ cable is not disturbed as I
>switch between the D-Link DI-524 and my lap-top computer..

You're NOT changing the cable length. You're changing the cable
wiring.

>Any Suggestions?

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558