Hi
I puchased a socket LP-E pcmcia card from an auction site.
Unfortunately the socket pcmcia card was supplied with a xircom connectivity cable and it doesn't work.
Is it possible to rewire an existing connectivity cable ?
I have attempted to use an oscilloscope on an RJ45 cable to see if I can compare the trace on the 'unknown' cable with a 'known good pcmcia card with cable' on the oscilloscope when using the 'ping' command,(but the cable is going nowhere, unterminated) and I find that I cannot get a good result.
Can I use an oscilloscope to view the result of a ping command ?
What results should I expect on the 8 pins of a RJ45 cable ?

thanx

GC

"glc" wrote in message ...

Hi
I puchased a socket LP-E pcmcia card from an auction site.
Unfortunately the socket pcmcia card was supplied with a xircom
connectivity cable and it doesn't work.
Is it possible to rewire an existing connectivity cable ?
I have attempted to use an oscilloscope on an RJ45 cable to see if I can
compare the trace on the 'unknown' cable with a 'known good pcmcia card
with cable' on the oscilloscope when using the 'ping' command,(but the
cable is going nowhere, unterminated) and I find that I cannot get a good
result.
Can I use an oscilloscope to view the result of a ping command ?
What results should I expect on the 8 pins of a RJ45 cable ?

thanx

GC

Ethernet (10--Base-T) using the UTP connector -- only uses pin 1/2 and pin
3/6 ... pin 4/5 are not used to avoid tip/ting POTS possible cross connect
mistakes
and pin 7/8 also not used to avoid other uses.
All covered in the IEEE 10-Base-T, EIA/TIA 568 standards and equivalent EU
standards

gb

gb wrote:
"glc" wrote in message ...

Hi
I puchased a socket LP-E pcmcia card from an auction site.
Unfortunately the socket pcmcia card was supplied with a xircom
connectivity cable and it doesn't work.
Is it possible to rewire an existing connectivity cable ?
I have attempted to use an oscilloscope on an RJ45 cable to see if I can
compare the trace on the 'unknown' cable with a 'known good pcmcia card
with cable' on the oscilloscope when using the 'ping' command,(but the
cable is going nowhere, unterminated) and I find that I cannot get a good
result.
Can I use an oscilloscope to view the result of a ping command ?
What results should I expect on the 8 pins of a RJ45 cable ?

thanx

GC


Ethernet (10--Base-T) using the UTP connector -- only uses pin 1/2 and pin
3/6 ... pin 4/5 are not used to avoid tip/ting POTS possible cross connect
mistakes
and pin 7/8 also not used to avoid other uses.
All covered in the IEEE 10-Base-T, EIA/TIA 568 standards and equivalent EU
standards

gb




Is that card only 10bt? Most anything made within the last few years is
10/100 which does use all pairs, and you have to use the right signals
on each pair for it to work.

In article oIXaf.2787$vC6.1314@trnddc05, James Sweet wrote:

Is that card only 10bt? Most anything made within the last few years is
10/100 which does use all pairs, and you have to use the right signals
on each pair for it to work.

100 base T and 1000 base T use the same wires. (1,2,3,6). Most modern
ethernet transcievers (2 years old or less) don't care if about the wiring
of the pair or if the pairs are reversed.

If you are connecting up to a modern hub such as a WiFi router with
a built in 4 port hub, then it will probably work as long as you get the
correct wires and keep the correct pairs (1,2 or 2,1) and (3,6 or 6,3)
no matter which set you connect to the other end.

I have an ethernet port next to my kitchen table so that if I have to
work on a computer, I can just plug it in. Since my hub is 10/100 autosensing
of direction and speed, I just keep a reversal cable nearby. That way
I can use the same cable to connect to the hub, or computer-computer
with older computers.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
You should have boycotted Google while you could, now Google supported
BPL is in action. Time is running out on worldwide radio communication.

Geoffrey S. Mendelson wrote:

In article oIXaf.2787$vC6.1314@trnddc05, James Sweet wrote:


Is that card only 10bt? Most anything made within the last few years is
10/100 which does use all pairs, and you have to use the right signals
on each pair for it to work.


100 base T and 1000 base T use the same wires. (1,2,3,6).

You sure about that? My recollection is that Gigabit uses all 8.

Most modern
ethernet transcievers (2 years old or less) don't care if about the wiring
of the pair or if the pairs are reversed.

Not sure what you mean by that. The electronics can't tell whether you
(consistently) swap the white+color and color, as long as you keep the
pairings intact. But they will certainly balk at mixing a wire from one
pair with a wire from another pair.

If you are connecting up to a modern hub such as a WiFi router with
a built in 4 port hub, then it will probably work as long as you get the
correct wires and keep the correct pairs (1,2 or 2,1) and (3,6 or 6,3)
no matter which set you connect to the other end.

I guess I'm still unsure what you mean. They're differential
transducers, so the difference is what's important.

I have an ethernet port next to my kitchen table so that if I have to
work on a computer, I can just plug it in. Since my hub is 10/100 autosensing
of direction and speed, I just keep a reversal cable nearby. That way
I can use the same cable to connect to the hub, or computer-computer
with older computers.

If by "direction" you mean X vs II, then it's probably a switch.
Or do you mean duplex?

Geoff.



--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

In article , CJT wrote:
You sure about that? My recollection is that Gigabit uses all 8.

I'll check, I've don't think so, but occasionaly I'm wrong. :-)

Not sure what you mean by that. The electronics can't tell whether you
(consistently) swap the white+color and color, as long as you keep the
pairings intact. But they will certainly balk at mixing a wire from one
pair with a wire from another pair.

Yes, that's true.


If by "direction" you mean X vs II, then it's probably a switch.
Or do you mean duplex?

All 10/100 hubs are by switches. How else could they adjust the speed?

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
You should have boycotted Google while you could, now Google supported
BPL is in action. Time is running out on worldwide radio communication.

Howdy!

"CJT" wrote in message
...
Geoffrey S. Mendelson wrote:

In article oIXaf.2787$vC6.1314@trnddc05, James Sweet wrote:


Is that card only 10bt? Most anything made within the last few years is
10/100 which does use all pairs, and you have to use the right signals
on each pair for it to work.


100 base T and 1000 base T use the same wires. (1,2,3,6).

You sure about that? My recollection is that Gigabit uses all 8.

1000BaseT is 2 pair, and most Gigibit uses 2 pair.

If they didn't they couldn't do Power Over Ethernet (PoE) injection
on the first pair, 4&5 B)

RwP

Geoffrey S. Mendelson wrote:

In article , CJT wrote:

You sure about that? My recollection is that Gigabit uses all 8.


I'll check, I've don't think so, but occasionaly I'm wrong. :-)


I Google'd for it, and this is the first reference I found. But I'm
fairly certain I've read it elsewhere, too, including in a textbook
on networking:

http://www.hardwaresecrets.com/article/231/2


Not sure what you mean by that. The electronics can't tell whether you
(consistently) swap the white+color and color, as long as you keep the
pairings intact. But they will certainly balk at mixing a wire from one
pair with a wire from another pair.


Yes, that's true.



If by "direction" you mean X vs II, then it's probably a switch.
Or do you mean duplex?


All 10/100 hubs are by switches. How else could they adjust the speed?

Not so. They can adjust the speed just as a switch does. The main
difference is that a hub lacks the logic to be selective about where
it forwards packets, and as a result doesn't need to maintain tables
of MAC addresses.


Geoff.




--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Ralph Wade Phillips wrote:

Howdy!

"CJT" wrote in message
...

Geoffrey S. Mendelson wrote:


In article oIXaf.2787$vC6.1314@trnddc05, James Sweet wrote:



Is that card only 10bt? Most anything made within the last few years is
10/100 which does use all pairs, and you have to use the right signals
on each pair for it to work.


100 base T and 1000 base T use the same wires. (1,2,3,6).

You sure about that? My recollection is that Gigabit uses all 8.


1000BaseT is 2 pair, and most Gigibit uses 2 pair.

Can you offer a cite?

If they didn't they couldn't do Power Over Ethernet (PoE) injection
on the first pair, 4&5 B)

RwP




--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

CJT wrote:

Geoffrey S. Mendelson wrote:

In article , CJT wrote:

You sure about that? My recollection is that Gigabit uses all 8.



I'll check, I've don't think so, but occasionaly I'm wrong. :-)


I Google'd for it, and this is the first reference I found. But I'm
fairly certain I've read it elsewhere, too, including in a textbook
on networking:

http://www.hardwaresecrets.com/article/231/2


FWIW, here's a cite with a little more impressive credentials:

http://www.cisco.com/en/US/tech/tk38...080091a86.html


Not sure what you mean by that. The electronics can't tell whether you
(consistently) swap the white+color and color, as long as you keep the
pairings intact. But they will certainly balk at mixing a wire from one
pair with a wire from another pair.



Yes, that's true.



If by "direction" you mean X vs II, then it's probably a switch.
Or do you mean duplex?



All 10/100 hubs are by switches. How else could they adjust the speed?


Not so. They can adjust the speed just as a switch does. The main
difference is that a hub lacks the logic to be selective about where
it forwards packets, and as a result doesn't need to maintain tables
of MAC addresses.


Geoff.






--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

On Sun, 6 Nov 2005, CJT wrote:

CJT wrote:

Geoffrey S. Mendelson wrote:

In article , CJT wrote:

You sure about that? My recollection is that Gigabit uses all 8.



I'll check, I've don't think so, but occasionaly I'm wrong. :-)


I Google'd for it, and this is the first reference I found. But I'm
fairly certain I've read it elsewhere, too, including in a textbook
on networking:

http://www.hardwaresecrets.com/article/231/2


FWIW, here's a cite with a little more impressive credentials:

http://www.cisco.com/en/US/tech/tk38...080091a86.html

Figure 7 of the cisco site shows all four pairs in use.

---
Lord, protect me from those to whom you speak directly
All salute the new age, and I hope nobody escapes

P. Thompson wrote:
On Sun, 6 Nov 2005, CJT wrote:

CJT wrote:

Geoffrey S. Mendelson wrote:

In article , CJT wrote:

You sure about that? My recollection is that Gigabit uses all 8.




I'll check, I've don't think so, but occasionaly I'm wrong. :-)


I Google'd for it, and this is the first reference I found. But I'm
fairly certain I've read it elsewhere, too, including in a textbook
on networking:

http://www.hardwaresecrets.com/article/231/2


FWIW, here's a cite with a little more impressive credentials:

http://www.cisco.com/en/US/tech/tk38...080091a86.html


Figure 7 of the cisco site shows all four pairs in use.

Precisely my point.

---
Lord, protect me from those to whom you speak directly
All salute the new age, and I hope nobody escapes


--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

CJT wrote:
P. Thompson wrote:

On Sun, 6 Nov 2005, CJT wrote:

CJT wrote:

Geoffrey S. Mendelson wrote:

In article , CJT wrote:

You sure about that? My recollection is that Gigabit uses all 8.





I'll check, I've don't think so, but occasionaly I'm wrong. :-)


I Google'd for it, and this is the first reference I found. But I'm
fairly certain I've read it elsewhere, too, including in a textbook
on networking:

http://www.hardwaresecrets.com/article/231/2


FWIW, here's a cite with a little more impressive credentials:

http://www.cisco.com/en/US/tech/tk38...080091a86.html


Figure 7 of the cisco site shows all four pairs in use.



I can say with certainty from experience that 10bt uses only two of the
pairs, but 100bt and gigabit both use all four pairs. You have to make
sure you use both wires from the same pair for each set of signals too,
if you mix and match it doesn't work for 100 or gig, but 10 is slow
enough that it doesn't seem to matter for short runs.

James Sweet wrote:

CJT wrote:

P. Thompson wrote:

On Sun, 6 Nov 2005, CJT wrote:

CJT wrote:

Geoffrey S. Mendelson wrote:

In article , CJT wrote:

You sure about that? My recollection is that Gigabit uses all 8.






I'll check, I've don't think so, but occasionaly I'm wrong. :-)


I Google'd for it, and this is the first reference I found. But I'm
fairly certain I've read it elsewhere, too, including in a textbook
on networking:

http://www.hardwaresecrets.com/article/231/2


FWIW, here's a cite with a little more impressive credentials:

http://www.cisco.com/en/US/tech/tk38...080091a86.html


Figure 7 of the cisco site shows all four pairs in use.




I can say with certainty from experience that 10bt uses only two of the
pairs, but 100bt and gigabit both use all four pairs. You have to make
sure you use both wires from the same pair for each set of signals too,
if you mix and match it doesn't work for 100 or gig, but 10 is slow
enough that it doesn't seem to matter for short runs.

I believe 100 uses only the same two pairs as 10. Only when you
move to gigabit are all 4 pairs used. Refer to the pages cited.
My understanding is that all four pairs must be present anyway,
in order for a cable to meet specs (I suspect that's to maintain
distances within the bundle, which could affect crosstalk). But
for 10/100, only half the wires are connected to anything.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

"James Sweet" wrote in message
news:zWCbf.12254$Ny6.9527@trnddc06...
CJT wrote:


http://www.cisco.com/en/US/tech/tk38...080091a86.html


Figure 7 of the cisco site shows all four pairs in use.


I can say with certainty from experience that 10bt uses only two of the
pairs, but 100bt and gigabit both use all four pairs. You have to make
sure you use both wires from the same pair for each set of signals too, if
you mix and match it doesn't work for 100 or gig, but 10 is slow enough
that it doesn't seem to matter for short runs.

INCORRECT, when the 100 Mb standard was being developed there were other
proposals that did call for all four (4) pairs to be used.
One argument 10 years ago -- that many installations (wiring closet to PC
desktop) were not compliant with EIA/TIA 568 (1992)-- and added undue cost
in rewiring these installations.

The referenced Cisco web page references the IEEE standards on which these
network solutions operate.

As Figure 7 shows, 1000BASE-T (1 Gb) works by using all four of the Category
5 pairs to achieve 1000 Mbps operation over the installed Category 5 copper
cabling. 1000 Mbps data rates are achieved by sending and receiving a 250
Mbps data stream over each of the four (4) pairs simultaneously (4 X 250
Mbps = 1 Gbps).

In contrast, 100BASE-TX uses two (2) pairs: one to transmit and one to
receive. Fast Ethernet on Copper (100BASE-TX) achieves 100 Mbps operation by
sending encoded symbols across the link at a symbol rate of 125 Mbaud.

Some in summary 10/100 Mb Ethernet solutions use 2 pairs and 1 Gb Ethernet
uses 4 pairs. All running on an EIA/TIA 568 compliant physical
infrastructure.

gb
IEEE member
Standards
Communications

"Ralph Wade Phillips" wrote in message
...


1000BaseT is 2 pair, and most Gigibit uses 2 pair.

If they didn't they couldn't do Power Over Ethernet (PoE) injection
on the first pair, 4&5 B)

RwP

Power over Ethernet has TWO OPTONS
It can work on the 2 spare pairs with 10 and 100 Mb Ethernet (which uses 2
pairs and has 2 spare pairs)
OR on 2 data pairs when used with 1 Gb Ethernet (which uses ALL 4 pairs).
Read it yourself.

http://www.poweroverethernet.com/art...?article_id=52
Part 4: How Power is Transferred Through the Cable

A standard CAT5 Ethernet cable has four twisted pairs, but only two (2) of
these pairs are used for 10BASE-T and 100BASE-T.

The specification allows two options for using these cables for power, shown
in Figure 2 and Figure 3:

a.. The spare pairs are used. Figure 2 shows the pair on pins 4 and 5
connected together and forming the positive supply, and the pair on pins 7
and 8 connected and forming the negative supply. (In fact, a late change to
the spec allows either polarity to be used).
b.. The data pairs are used. Since Ethernet pairs are transformer coupled
at each end, it is possible to apply DC power to the center tap of the
isolation transformer without upsetting the data transfer. In this mode of
operation the pair on pins 3 and 6 and the pair on pins 1 and 2 can be of
either polarity.

gb

Simple question on your excellent response which answers the 2 pair vs. 4
pair question:

100BaseT is 100Mbps full duplex. This means it can pass 100Mbps in both
directions simultaneously. This is done by using a pair of wires in each
direction (uplink=send/downlink=receive). You indicate that GbE is a full
1000Mbps and uses the 4 pairs which each send 250Mbps. Does this imply that
GbE is now half duplex or that the send uses 2 pairs and the receive another
pair? What is the maximum SIMULTANEOUS transmission rates in the uplink and
downlink? Can you provide some insight since I had always assumed GbE was
also 1000Mbps full duplex like 100BaseT Fast Ethernet.

Thanks in advance for your insight here. It is important to understand if
GbE is 5 times or 10 times faster than FE.

Bob


"gb" wrote in message
. ..

INCORRECT, when the 100 Mb standard was being developed there were other
proposals that did call for all four (4) pairs to be used.
One argument 10 years ago -- that many installations (wiring closet to PC
desktop) were not compliant with EIA/TIA 568 (1992)-- and added undue cost
in rewiring these installations.

The referenced Cisco web page references the IEEE standards on which these
network solutions operate.

As Figure 7 shows, 1000BASE-T (1 Gb) works by using all four of the
Category
5 pairs to achieve 1000 Mbps operation over the installed Category 5
copper
cabling. 1000 Mbps data rates are achieved by sending and receiving a 250
Mbps data stream over each of the four (4) pairs simultaneously (4 X 250
Mbps = 1 Gbps).

In contrast, 100BASE-TX uses two (2) pairs: one to transmit and one to
receive. Fast Ethernet on Copper (100BASE-TX) achieves 100 Mbps operation
by
sending encoded symbols across the link at a symbol rate of 125 Mbaud.

gb
IEEE member
Standards
Communications

Howdy!

"gb" wrote in message
...
"Ralph Wade Phillips" wrote in message
...


1000BaseT is 2 pair, and most Gigibit uses 2 pair.

If they didn't they couldn't do Power Over Ethernet (PoE)
injection
on the first pair, 4&5 B)

RwP

Power over Ethernet has TWO OPTONS
It can work on the 2 spare pairs with 10 and 100 Mb Ethernet (which uses 2
pairs and has 2 spare pairs)
OR on 2 data pairs when used with 1 Gb Ethernet (which uses ALL 4 pairs).
Read it yourself.

You are, of course, right.

That's what I get for "extending from previous learning experiences"
.... PoE has always been on pins 4 &5 in my past experience, and I've got at
least two customers with 100BaseTX stuff running over PoE connections
(webcams, both of them) to a gigabit switch (a Catalyst), with no seperate
injector.

Thanks for the education!

RwP

"Bob Shuman" wrote in message
...
Simple question on your excellent response which answers the 2 pair vs. 4
pair question:

100BaseT is 100Mbps full duplex. This means it can pass 100Mbps in both
directions simultaneously. This is done by using a pair of wires in each
direction (uplink=send/downlink=receive). You indicate that GbE is a full
1000Mbps and uses the 4 pairs which each send 250Mbps. Does this imply
that
GbE is now half duplex or that the send uses 2 pairs and the receive
another
pair? What is the maximum SIMULTANEOUS transmission rates in the uplink
and
downlink? Can you provide some insight since I had always assumed GbE was
also 1000Mbps full duplex like 100BaseT Fast Ethernet.

Thanks in advance for your insight here. It is important to understand if
GbE is 5 times or 10 times faster than FE.

Bob


Bob -

Excellent question, and I am laughing .. because I was never in favor of
using with copper cabling with GbE (I preferred the usage of fiber optic
cabling).

I have not participated or even kept up with GbE and the current 10 GbE
discussions (and roadblocks) for several years.

1000BASE-T is one (1) of the fours (4) physical layers or transceivers
defined by the two GbE (Gigabit Ethernet) standards:
IEEE 802.3z or 1000BASE-X and IEEE 802.3ab or 1000BASE-T.

1000BASE-X supports:
Multimode fiber media
Single-mode fiber media and
A short-reach, 25-meter Copper media jumper.

Because most of the cabling installed inside buildings today is Category 5
copper, the IEEE 802.3 1000BASE-T standard supports GbE operation over the
Category 5 cabling systems installed according to the specifications of
ANSI/TIA/EIA-568A (1992, revision A in 1995).

I will let you read the Cisco web page, Figure 7 answers your question
http://www.cisco.com/en/US/tech/tk38...080091a86.html

I read the Cisco page (mostly marketing spin) and found the following
sentence that answered my question:

"1000 Mbps data rates are achieved by sending and receiving a 250 Mbps data
stream over each of the four pairs simultaneously (4 X 250 Mbps = 1 Gbps)."

This implies that the 4 twisted pairs are simultaneously both sending and
receiving separate 250Mbps data streams giving the 1000Mbps throughput in
both directions. The picture showing hybrids in each twisted pair
reinforces that each wire pair is indeed full duplex and provides additional
detail on the physical link rates. This is what I take away from this, but
if I have misunderstood, please correct me.

On your preference for optical fiber or even coaxial copper cable, yes,
Fiber does seem to be better for many applications since it provides
separate send and receive paths making it more immune to noise and
increasing the allowable distance, especially for Single Mode Fiber (SMF).
But, this comes at a high price since the cost of optical GbE interfaces,
especially SMF are much more than for the copper RJ45.

RJ45 GbE seems to be the best way to interconnect network elements that are
in close physical proximity (i.e. the same data cabinet) since it can be
done very cheaply. As the article also explained, it is also a good way to
increase bandwidth to end users when Cat5 already exists in a facility's
wiring closets to desktops.

This was a very good thread. Thanks for correcting the initial reply and
providing these links.

Bob

"gb" wrote in message
...
"Bob Shuman" wrote in message
...
Simple question on your excellent response which answers the 2 pair vs.
4
pair question:

100BaseT is 100Mbps full duplex. This means it can pass 100Mbps in both
directions simultaneously. This is done by using a pair of wires in
each
direction (uplink=send/downlink=receive). You indicate that GbE is a
full
1000Mbps and uses the 4 pairs which each send 250Mbps. Does this imply
that
GbE is now half duplex or that the send uses 2 pairs and the receive
another
pair? What is the maximum SIMULTANEOUS transmission rates in the uplink
and
downlink?

Bob -

1000BASE-T is one (1) of the fours (4) physical layers or transceivers
defined by the two GbE (Gigabit Ethernet) standards:
IEEE 802.3z or 1000BASE-X and IEEE 802.3ab or 1000BASE-T.

1000BASE-X supports:
Multimode fiber media
Single-mode fiber media and
A short-reach, 25-meter Copper media jumper.

Because most of the cabling installed inside buildings today is Category 5
copper, the IEEE 802.3 1000BASE-T standard supports GbE operation over the
Category 5 cabling systems installed according to the specifications of
ANSI/TIA/EIA-568A (1992, revision A in 1995).

I will let you read the Cisco web page, Figure 7 answers your question

http://www.cisco.com/en/US/tech/tk38...080091a86.html

"Bob Shuman" wrote in message
...
I read the Cisco page (mostly marketing spin) and found the following
sentence that answered my question:

"1000 Mbps data rates are achieved by sending and receiving a 250 Mbps
data
stream over each of the four pairs simultaneously (4 X 250 Mbps = 1
Gbps)."

This implies that the 4 twisted pairs are simultaneously both sending and
receiving separate 250Mbps data streams giving the 1000Mbps throughput in
both directions. The picture showing hybrids in each twisted pair
reinforces that each wire pair is indeed full duplex and provides
additional
detail on the physical link rates. This is what I take away from this,
but
if I have misunderstood, please correct me.

On your preference for optical fiber or even coaxial copper cable, yes,
Fiber does seem to be better for many applications since it provides
separate send and receive paths making it more immune to noise and
increasing the allowable distance, especially for Single Mode Fiber (SMF).
But, this comes at a high price since the cost of optical GbE interfaces,
especially SMF are much more than for the copper RJ45.

RJ45 GbE seems to be the best way to interconnect network elements that
are
in close physical proximity (i.e. the same data cabinet) since it can be
done very cheaply. As the article also explained, it is also a good way
to
increase bandwidth to end users when Cat5 already exists in a facility's
wiring closets to desktops.

This was a very good thread. Thanks for correcting the initial reply and
providing these links.

Bob


Bob,

One note - that is sometime forgotten concerning 1000BASE-X
While it does support fiber media (multimode & single-mode), the
short-reach, 25-meter copper media jumper is actually a shielded (or
"screened" as the Europeans say) -- which is not UTP Cat5.

The other advantage of copper based cables and jumpers is that their
connectors usually require a smaller physical footprint -- which is
important for high density blades or cards in network equipment. I find its
usage predominantly in data centers with high concentrations (and short
lengths) of servers and network gear.

The reason for my fiber bias is that it permits future bandwidth
enhancements.
Twisted copper cable is near maximum practical bandwidth usage - and coaxial
copper is not far behind in capacity.

Now back to my wireless reading about Worldwide Interoperability for
Microwave Access -- WiMAX (IEEE 802.16)
http://www.wimaxforum.org/home..

gb

gb

I just configured and integrated a WiMAX 3500 system for evaluation in a
laboratory environment... I am not yet very knowledgeable on WiMAX
(802.16d) but have considerable experience in the WiFi (802.11a/b/g) arena.
We used RJ45 copper GbE from the WiMAX Base Station to a switch so this
discussion was timely.

Bob

"gb" wrote in message
. ..
Bob,
Now back to my wireless reading about Worldwide Interoperability for
Microwave Access -- WiMAX (IEEE 802.16)
http://www.wimaxforum.org/home..

gb