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DTE and DCE

Dear all,

As i know from my ccna study when i connect a Router(DTE) to a computer(DTE) i need to use a cross cable.

In my lab i tryed to do this with straight cable and it also worked.

How can it be? is the router can work either way?

1 ACCEPTED SOLUTION

Accepted Solutions

Re: DTE and DCE

The feature is called auto MDI/MDIX.

Which is there by default on some ports actually it is an hardware based application which detects the signaling.

The port auto detect the nature of the cable and make the necessary adjustments in signaling.

regards,

shri :)

5 REPLIES

Re: DTE and DCE

HI,

Are U sure its a straight cable.

I see, there are no Techical documents justifying the same.

Best Regards,

Guru Prasad R

Silver

Re: DTE and DCE

Yes, you are correct

A DTE is a Host computer system and the DTE main DTE signals are

DTR

RTS

TX

RX

DCE signals are

RTS

CTS

CD

TX

RX

Some devices auto sense the signals from the DTE Host and can change their orientation. That is why it works with a straight as well as a rolled cable. However you should always try to use the proper cabling for not all interfaces on all devices are auto-sensing....

Re: DTE and DCE

The feature is called auto MDI/MDIX.

Which is there by default on some ports actually it is an hardware based application which detects the signaling.

The port auto detect the nature of the cable and make the necessary adjustments in signaling.

regards,

shri :)

New Member

Re: DTE and DCE

cisco 2960 to 2960 straight - work

pc(winxp) to pc(win2003) straight - work

2600 to 2500 straight - didn't work

pc to 2600 straight - work

pc to 2960 cross - work

What is happening? is the rules of network is changing?

Re: DTE and DCE

Hi Arik,

You can follow another thread in LAN, Switching and Routing, for another prospective:

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Network%20Infrastructure&topic=LAN%2C%20Switching%20and%20Routing&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.2cbf13fe

If we take this question to the physical level, routers, wireless access point Ethernet ports, and PC NICs all send using pins 1 and 2, whereas hubs and switches send using pins 3 and 6. Straight-through cables are used when connecting devices that use the opposite pairs of pins to transmit data (Tx to Rx and Rx to Tx), if the devices are the same (use the same pins for Tx and Rx) then we must use a cross-over cable to cross the transmission.

And as Edison pointed out, before Auto-MDIX, we had to use a crossover cable to connect a switch to a switch, with Auto-MDIX there is only one thing to consider, if speed/duplex are manually configured Auto-MDIX is disabled, and we'll have to use a crossover cable.

NOTE the 2960 does support the auto-MDIX feature and it is enabled by default

BR,

Mohammed Mahmoud.

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