NULL Modem cable (cross-over)
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Hi all, I want to ask if anyone knows how to know a null modem cable according to the resistance or voltage of its pins?!! Regards,
A Null-Modem-Cable is a normal serial cable (usually RS-232 to RS-232) with a certain pin-to-pin mapping. If you need one, and have a serial cable you can easily access, you could make it yourself. I have some trouble understanding what you are trying to achieve. Could you explain what you are trying to do?
Cheers, Sebastian -- Ceterum censeo, borlandem esse delendam.
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A Null-Modem-Cable is a normal serial cable (usually RS-232 to RS-232) with a certain pin-to-pin mapping. If you need one, and have a serial cable you can easily access, you could make it yourself. I have some trouble understanding what you are trying to achieve. Could you explain what you are trying to do?
Cheers, Sebastian -- Ceterum censeo, borlandem esse delendam.
Hi Sebastian, Thanks for your reply. I mean if I have a cable, how to check if it is a null modem cable or not because the problem is I have asked a saler in a computer shop to give me a null modem cable and he did gave me a cable but when I tried to communicate two DCE devices it didn't work!! So is there a way to check the cable according to the resistance/voltage between pins from both ends? Regards,
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Hi Sebastian, Thanks for your reply. I mean if I have a cable, how to check if it is a null modem cable or not because the problem is I have asked a saler in a computer shop to give me a null modem cable and he did gave me a cable but when I tried to communicate two DCE devices it didn't work!! So is there a way to check the cable according to the resistance/voltage between pins from both ends? Regards,
the pins are connected differently. Google up the pinout/wiring diagrams and use a multimeter to check connectivity.
-- CleaKO The sad part about this instance is that none of the users ever said anything [about the problem]. Pete O`Hanlon Doesn't that just tell you everything you need to know about users?
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the pins are connected differently. Google up the pinout/wiring diagrams and use a multimeter to check connectivity.
-- CleaKO The sad part about this instance is that none of the users ever said anything [about the problem]. Pete O`Hanlon Doesn't that just tell you everything you need to know about users?
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Thankx Dan for your replay. Could you be more specific. I mean what am I going to measure voltage? and what values I should expect? Regards,
You're not measuring voltage. You're measuring resistance, or in your case, you're looking for the lack of it between two pins.
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
2006, 2007