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[kcbeersnob]

I've just switched to an ISP that ran fiber to my house.  My DIR-655 does not recognize the ethernet cable they ran from the modem, which is installed in a box outside my house (the WAN light remains off and the Status page indicates no cable in the port.  It turns out they used a Cat-3 cable, which I suspect is the problem.

Additional information:

• Every other cable I test (Cat 5 or 5e) on the router works. 
• All other devices (PC's and an old DI-604 router) recognize the Cat-3 cable.

The cable company is coming out today to have a look, but they think I'm crazy.  I thought I read somewhere before buying the router a couple years ago that you have to use Cat5 or better with this router.

[kcbeersnob]

The ISP just came out and replaced the Cat 3 cable with Cat 5.  I've got connectivity on the router now.

I've got a request for the good people at D-Link:  If there are indeed specific cable requirements for this device, it would be nice to see them clearly documented in the specs.

[EddieZ]

I think there are no specific cable requirements for the D-link. These cable requirements are generic for LAN's since the condition and length of the cable also needs to be taken into account for a cat 3 cable.

[davevt31]

You may have needed to go into the router config and lock down the WAN speed as Cat 3 is only capable of 10Mbs.  Cat 5 is capable of the higher speeds.

[Reinvented]

You may have needed to go into the router config and lock down the WAN speed as Cat 3 is only capable of 10Mbs.  Cat 5 is capable of the higher speeds.

So, with that in mind, are you saying "Auto" doesn't work???

And why would anyone want to use cat 3 cables?  Cat 5 and above are standard.  No reason that anyone should be using anything less..

[EddieZ]

So, with that in mind, are you saying "Auto" doesn't work???

And why would anyone want to use cat 3 cables?  Cat 5 and above are standard.  No reason that anyone should be using anything less..

That's not what he is saying. AUto might not work. But since there was no opportunity to test this...The same can occur with wireless adapters that connect fine to router when set to 10 or 100, but fail to connect when set to Auto.

Some prefab installations (houses) contain older and cheaper CAT 3 wiring. And ofcourse CAT 5 has not always been around.

[davevt31]

Cat 3 is still considered a standard cable. It was probably being used by the installer so that they can limit the connection speed (not that an ISP would try to limit things  )

[Fatman]

It is not that there is a cable requirement specific to this router, but that the cable requirement is recognized across the industry.  The specification in the IEEE802.3 spec is is based on cable performance, not designations.  However it is commonly read that the below is true.

10BaseT requires Cat 3
100BaseTX requires Cat 5
1000BaseT requires Cat 5e

That said you should still have been able to generate a 10BaseT connection.  My best guess is, that it was, as already guessed, a autonegotiation problem.

Installers would use Catagory 3 cable because they are cheap, invested in miles of the stuff in the early 90s or before, or both.  It is however at best a cut corner, they should save it for thier PSTN installations.

**Edited forthe ruination of grammar.  I swear I wan't taught English grammar by a school of blind-deaf-mute Tibetan monks.**

[thecreator]

It is not that there is a cable requirement specific to this router, but that the cable requirement is recognized across the industry.  The specification in the IEEE802.3 spec is is based on cable performance, not designations.  However it is commonly read that the below is true.

10BaseT requires Cat 3
100BaseTX requires Cat 5
1000BaseT requires Cat 5e

Hi Fatman,

Is the Cable that comes with the D-Link DIR-655 Router, a Cat 5 e? How can you tell looking at the Cables?

[EddieZ]

Hi Fatman,

Is the Cable that comes with the D-Link DIR-655 Router, a Cat 5 e? How can you tell looking at the Cables?

It is. And it is printed on the cable 

[Backdoctor52]

I can tell you what happens if you have a CAT5 or less, running more than 50 ft from the DIR-655 to a computer.
If the link speed is set to auto or more than 10Mbps (100/1000) it will have problems connecting and keeping the connection, since it will try to connect at the highest speed, and will only constantly connect (and stay connected) when set to 10Mbps.
I have had this problem with poor quality CAT5 but not with CAT5E or CAT6 with this router.

[v_lestat]

1000BaseT requires Cat 5e

that is not true

Cat5e is only capable of 350mhz 400mbps
Cat6 is 1000mbps

period.

cat5e is used as a cheaper alternative by LAZY and CHEAP IT people and installers.

if you doubt my words then just do a true test with iperf and you will INSTANTLY see the difference.
run iperf with Cat5e then Cat6,,,, you'll see

not only that but Cat6 is tested for crosstalk and fade where Cat5e is not, it is only tested for connectivity on the twisted pairs.

1000mbps ethernet demands quality cable to reduce or eliminate crosstalk and interference between the twisted pairs. thats why a GOOD cat6 cable has the twisted pairs twised right up to the point where the cat6 connector lances the wire, where as Cat5e does not.

[Fatman]

The specification in the IEEE802.3 spec is is based on cable performance, not designations.  However it is commonly read that the below is true.

10BaseT requires Cat 3
100BaseTX requires Cat 5
1000BaseT requires Cat 5e

In the future please quote my entire thought if not my entire post, your partial quote makes it sound like I had stated something I hadn't.

Your statement that 1000BaseT will not work with less than Cat 6 is false.  Amusingly 1000BaseTX does carry a strict recommendation of Cat 6.

I see stable 1000mbps connections all day long, I recommend Cat 5e or better because as you pointed out Cat 6 is expensive, especially with copper prices rising and the knowledge that performance mania won't be dissuaded.

I have personally run long term tests using a approximately 50m run between 2 gigabit switches using Cat 5 and have gotten (iSCSI data) throughput that was much better than 900Mbps.  I don't know how familiar you are with speed tests in real world scenarios, however most people don't get that raw throughput with their hardware, let alone as data throughput after a complex protocol like iSCSI..

To be more specific my cable was run unshielded as part of a bundle of approximately 100 cables (plus being ran next to power and fluorescent lighting on the way) into a rack where our lab infrastructure resides.  The interfaces were a DGE-550T and the built in interface on a DSN-3200, the switches were 2 DXS-3250s.  This is an old 10/100 installation that we just dropped gigabit switches in on, not what I recommend, but not unusable.

That said I do recommend that anyone install the highest quality cable they can afford as it will future proof you, and provide the potential for better performance.  The recommendations I provided are based on long held industry recommendations and just as I stated are not specified in any standards.

So, back to where we started, some things will work despite being below recommendation, there is nothing that tells either end what kind of cable is being used, if the run is short or your conditions are favorable you can get away with sub par media.  I wouldn't hedge any bets on it though.  With that in mind I will stick to my above recommendations.

[Lycan]

1000BaseT requires Cat 5e

that is not true

Cat5e is only capable of 350mhz 400mbps
Cat6 is 1000mbps

period.

cat5e is used as a cheaper alternative by LAZY and CHEAP IT people and installers.

if you doubt my words then just do a true test with iperf and you will INSTANTLY see the difference.
run iperf with Cat5e then Cat6,,,, you'll see

not only that but Cat6 is tested for crosstalk and fade where Cat5e is not, it is only tested for connectivity on the twisted pairs.

1000mbps ethernet demands quality cable to reduce or eliminate crosstalk and interference between the twisted pairs. thats why a GOOD cat6 cable has the twisted pairs twised right up to the point where the cat6 connector lances the wire, where as Cat5e does not.

I have a 100% gigabit netwrok running in my home comprised of entirely cat5e. I see close to 850Mbps through my network, and and actual rate of 106+MBps.
So your statement about cat5e is completely untrue.

[EddieZ]

Same here. Respectable throughput, more or less identical as Lycan. And using CAT5e (about 40 metres)