Re: OT, proper phone wire question?/Twists Guage ?
On Fri, Nov 28, 2003 at 05:24:35PM +0800, David Palmer. wrote:
[suggestion of heavier guage wire for network]
| Good thinking.
| In legal building standards for example, the standards specified are
| 'minimum required without having to go to jail.'
| Going up one more guage in wire size does indeed reduce resistance and
| associated energy waste in heat given off, and allows the maximum amount
| of energy to arrive at the appliance concerned, with the associated
| economic factor. There's the greater initial cost which concerns the
| short-sighted initially, but cost savings over the longer term which
| soon recoup the initial investment, and mean money in the bank
| thereafter for those that are capable of thinking beyond the trapezium.
However, there is a difference between power transmission and digital
signalling.
While what you say sounds correct for power transmission. (I don't
remember all the details from class, which was around 7 or 8 years
ago).
For digital signalling, though, I'd take John's advice about speaker
wire not being suitable. His advice sounds correct for the digital
signalling environment you are in.
-D
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Re: OT, proper phone wire question?/Twists Guage ?
On Wed, 26 Nov 2003 18:30:00 -0500 lee [EMAIL PROTECTED] wrote: On Tuesday 18 November 2003 15:36, Derrick 'dman' Hudson wrote: Why are twists so important and why do the faster technologies need more twists in the cable? As an electric signal varies along a pair of wires, a magnetic field around the wires is created and then collapses. This field will induce a current in another wire that passes through the field. That induced current is noise, because it intereferes with the electric current (signal) that is intentially being sent over that wire. Twisting the wires reduces the size of the generated magnetic field, and also reduces the cable's ability to pick up a signal from a nearby magnetic field. For voice-grade telephone, no twists are needed most of the time. For better signalling and less noise, get more twists. Using Cat 0 or Cat 3 should be fine, but the Cat 3 will cost more money. You *may* have noise problems with Cat 0 which will hurt your ability to connect, maintain a connection, and will limit transfer rates. Basically more is better when it comes to twists, but also more costs more. It's up to you to find the desired return-on-investment for cable quality. HTH, -D Thank you very much for the discussion on twists, I have a question..what about actual wire size..cat 3 and 5 are usually 22 or 24 guage..suppose one was to use say 18 guage speaker wire..it's twisted(like cat), it's unshielded(like cat)..but a bit larger..less resistance is my thinking..where am i wrong here..not enuff twists perhaps? Thank you all very very much for your time.. Lee Good thinking. In legal building standards for example, the standards specified are 'minimum required without having to go to jail.' Going up one more guage in wire size does indeed reduce resistance and associated energy waste in heat given off, and allows the maximum amount of energy to arrive at the appliance concerned, with the associated economic factor. There's the greater initial cost which concerns the short-sighted initially, but cost savings over the longer term which soon recoup the initial investment, and mean money in the bank thereafter for those that are capable of thinking beyond the trapezium. Regards, David. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: OT, proper phone wire question?/Twists Guage ?
- Original Message - From: lee [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, November 26, 2003 17:30 Subject: Re: OT, proper phone wire question?/Twists Guage ? On Tuesday 18 November 2003 15:36, Derrick 'dman' Hudson wrote: Why are twists so important and why do the faster technologies need more twists in the cable? As an electric signal varies along a pair of wires, a magnetic field around the wires is created and then collapses. This field will induce a current in another wire that passes through the field. That induced current is noise, because it intereferes with the electric current (signal) that is intentially being sent over that wire. Twisting the wires reduces the size of the generated magnetic field, and also reduces the cable's ability to pick up a signal from a nearby magnetic field. For voice-grade telephone, no twists are needed most of the time. For better signalling and less noise, get more twists. Using Cat 0 or Cat 3 should be fine, but the Cat 3 will cost more money. You *may* have noise problems with Cat 0 which will hurt your ability to connect, maintain a connection, and will limit transfer rates. Basically more is better when it comes to twists, but also more costs more. It's up to you to find the desired return-on-investment for cable quality. HTH, -D Thank you very much for the discussion on twists, I have a question..what about actual wire size..cat 3 and 5 are usually 22 or 24 guage..suppose one was to use say 18 guage speaker wire..it's twisted(like cat), it's unshielded(like cat)..but a bit larger..less resistance is my thinking..where am i wrong here..not enuff twists perhaps? Thank you all very very much for your time.. Lee The reason for twisting wires is to reduce 'common mode' noise and it depends on the noise environment that the wire passes through. More twists mean a wider range of environments can be handled. Since the voltage induced in both wires is closer to the same amount. If you would like to experment try connecting one wire of a pair and a good ground to an oscilloscope and look at the noise. Modern telephones require very little current to operate properly so 22 to 24 gauge is entirely adequate and electronics can require much less, if you do not adhere to telco specs. Therefore I would not expect any gain from 18 guage wire. My Opinion for what its worth; Hoyt -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: OT, proper phone wire question?/Twists Guage ?
lee writes: suppose one was to use say 18 guage speaker wire..it's twisted(like cat), it's unshielded(like cat)..but a bit larger..less resistance is my thinking..where am i wrong here..not enuff twists perhaps? The difference in resistance is unimportant. The speaker wire will have different characteristic impedance due to being larger and having a different number of twists per foot. This will cause reflections that will interfere with transmission. The speaker wire also is not designed as transmission line and so will not be of uniform and consistent impedance. The insulation on the speaker wire may also be lossy at the frequencies of interest. -- John Hasler [EMAIL PROTECTED] (John Hasler) Dancing Horse Hill Elmwood, WI -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: OT, proper phone wire question?/Twists Guage ?
On Wed, 26 Nov 2003 18:30:00 -0500 lee [EMAIL PROTECTED] wrote: Thank you very much for the discussion on twists, I have a question..what about actual wire size..cat 3 and 5 are usually 22 or 24 guage..suppose one was to use say 18 guage speaker wire..it's twisted(like cat), it's unshielded(like cat)..but a bit larger..less resistance is my thinking..where am i wrong here..not enuff twists perhaps? Thank you all very very much for your time.. Lee I've never actually tried it, but I suspect you would have a hard time getting 18 gauge wire to fit in an RJ11 (common for phones) or RJ45 (common for networks) plug. They usually make them with very little room to spare so you don't have to worry about 2 wires in one groove, etc. Not to mention the fact that if they enlarge the plug too much it won't fit in the jack any more... HTH, Jacob - GnuPG Key: 1024D/16377135 Windows: The first user interface where you click Start to turn it off. pgp0.pgp Description: PGP signature
Re: OT, proper phone wire question?/Twists Guage ?
On Tuesday 18 November 2003 15:36, Derrick 'dman' Hudson wrote: Why are twists so important and why do the faster technologies need more twists in the cable? As an electric signal varies along a pair of wires, a magnetic field around the wires is created and then collapses. This field will induce a current in another wire that passes through the field. That induced current is noise, because it intereferes with the electric current (signal) that is intentially being sent over that wire. Twisting the wires reduces the size of the generated magnetic field, and also reduces the cable's ability to pick up a signal from a nearby magnetic field. For voice-grade telephone, no twists are needed most of the time. For better signalling and less noise, get more twists. Using Cat 0 or Cat 3 should be fine, but the Cat 3 will cost more money. You *may* have noise problems with Cat 0 which will hurt your ability to connect, maintain a connection, and will limit transfer rates. Basically more is better when it comes to twists, but also more costs more. It's up to you to find the desired return-on-investment for cable quality. HTH, -D Thank you very much for the discussion on twists, I have a question..what about actual wire size..cat 3 and 5 are usually 22 or 24 guage..suppose one was to use say 18 guage speaker wire..it's twisted(like cat), it's unshielded(like cat)..but a bit larger..less resistance is my thinking..where am i wrong here..not enuff twists perhaps? Thank you all very very much for your time.. Lee -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
