Can a standard NIC be triggered to send an electrical signal?
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Posted by NANewbie on August 30, 2005, 8:28 am
Please log in for more thread options Hi! Does anyone know if a standard NIC can be configured to send an electrical signal down a cable? If yes, then can we write a program that can do that? How? Thanks. ------------------------------------- ##-----------------------------------------------## Article posted with Cabling-Design.com Newsgroup Archive http://www.cabling-design.com/forums no-spam read and post WWW interface to your favorite newsgroup - comp.dcom.lans.ethernet - 3309 messages and counting! ##-----------------------------------------------## | ||||||||||||||||
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Posted by Tomi Holger Engdahl on August 31, 2005, 1:55 pm
Please log in for more thread options genielicious_at_yahoo_dot_com@foo.com (NANewbie) writes: To my knowledge there is no standard configuration / feature for NICs to send any single pulses to the line when commanded. With a normal 10Base-T Ethernet card normally when nothing is transmitted, the line is silent (only some link pulses could sent every now and then). When you transmit a packet, the Ethernet card sends a series of bits to the line presenting the data of the data packet. So with such card you just need to send a packet, and the card sends a set of electrical signal pulses to the line... Any packet will do. With a TCP/IP networking send out ARP or UDP packet. With 100 Mbit/s Ethernet (100Base-TX) things are not that simple.. When Ethernet card is transmitting data, you get bits on the line. But even when the card is not transmitting any actual data, there are bits traveling through the wire (a known bit pattern that keeps the data clocks on the oppostite ends of the link syncronized). -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/ | ||||||||||||||||
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Posted by NANewbie on September 1, 2005, 5:06 am
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Say I write a program that creates a packet and inject it on the line. The packet will be sent as a set of electrical signal pulses to the line, as you say. What happens when they encounter an open circuit in the cable, do they get reflected due to the impedance mismatch? If the data is reflected, would it be too corrupted that my program won't be able to recognise it as the one it sent earlier? ------------------------------------- Tomi Holger Engdahl wrote: > genielicious_at_yahoo_dot_com@foo.com (NANewbie) writes:
>> Hi!
>> >> Does anyone know if a standard NIC can be configured to send an >> electrical >> signal down a cable? If yes, then can we write a program that can >> do that? >> How? Thanks. > To my knowledge there is no standard configuration / feature for NICs
> to send any single pulses to the line when commanded. > With a normal 10Base-T Ethernet card normally when nothing
> is transmitted, the line is silent (only some link pulses > could sent every now and then). When you transmit a packet, > the Ethernet card sends a series of bits to the line > presenting the data of the data packet. > So with such card you just need to send a packet, and the
> card sends a set of electrical signal pulses to the line... > Any packet will do. > With a TCP/IP networking send out ARP or UDP packet. > With 100 Mbit/s Ethernet (100Base-TX) things are not that simple..
> When Ethernet card is transmitting data, you get bits on the line. > But even when the card is not transmitting any actual data, there > are bits traveling through the wire (a known bit pattern that > keeps the data clocks on the oppostite ends of the link syncronized). ##-----------------------------------------------## Article posted with Cabling-Design.com Newsgroup Archive http://www.cabling-design.com/forums no-spam read and post WWW interface to your favorite newsgroup - comp.dcom.lans.ethernet - 3330 messages and counting! ##-----------------------------------------------## | ||||||||||||||||
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Posted by Tomi Holger Engdahl on September 1, 2005, 9:35 am
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genielicious_at_yahoo_dot_com@foo.com (NANewbie) writes: > Say I write a program that creates a packet and inject it on the line. The
> packet will be sent as a set of electrical signal pulses to the line, as > you say. What happens when they encounter an open circuit in the cable, > do they get reflected due to the impedance mismatch? Yes. > If the data is
> reflected, would it be too corrupted that my program won't be able to > recognise it as the one it sent earlier? In 10Base-T ethernet system when the card sent out the pulse to the wire pair used ot transmit, and it hits an impedance mismatch, some part of the signal (or all) gets reflected back through that pair. When the reflected back signal reaches the card, it is coming to it though the transmit pair. There is no receiver on transmitting pair. The card does not know anythign about the signal being reflected on the cable. -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/ | ||||||||||||||||
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Posted by NANewbie on September 2, 2005, 1:50 am
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Ohh... ok... hmm... I really have very limited knowledge about what a standard NIC is capable of.... Do you by any chance know any online material or books (doubt I can find them at the library though) where I can read up about the functionality of a standard NIC? I need to know what it can and cannot do before I come to a dead end again. I tried looking for it before, but this kind of info seems hard to find. Thanks for enlightening me. Really appreciate it. Cheers! ------------------------------------- Tomi Holger Engdahl wrote: > genielicious_at_yahoo_dot_com@foo.com (NANewbie) writes:
>> Say I write a program that creates a packet and inject it on the
>> line. The >> packet will be sent as a set of electrical signal pulses to the >> line, as >> you say. What happens when they encounter an open circuit in the >> cable, >> do they get reflected due to the impedance mismatch? > Yes.
>> If the data is
>> reflected, would it be too corrupted that my program won't be able >> to >> recognise it as the one it sent earlier? > In 10Base-T ethernet system when the card sent out the pulse
> to the wire pair used ot transmit, and it hits an impedance > mismatch, some part of the signal (or all) gets reflected back > through that pair. When the reflected back signal reaches > the card, it is coming to it though the transmit pair. > There is no receiver on transmitting pair. The card does not > know anythign about the signal being reflected on the cable. ##-----------------------------------------------## Article posted with Cabling-Design.com Newsgroup Archive http://www.cabling-design.com/forums no-spam read and post WWW interface to your favorite newsgroup - comp.dcom.lans.ethernet - 3336 messages and counting! ##-----------------------------------------------## | ||||||||||||||||
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>
> Does anyone know if a standard NIC can be configured to send an electrical
> signal down a cable? If yes, then can we write a program that can do that?
> How? Thanks.