28 AWG jump line 'bony mystery' over the past few years, some manufacturers have been launched 28 AWG jump line, the jumper wire diameter smaller, help to improve air circulation around active devices, and because the can relieve the crowded situation and bending radius smaller, benefit in high-density jumper cable management.
Although caused some controversy in the industry, because at the beginning of the jump line more has not been recognized standard ANSI/TIA cabling, standard twisted-pair structured cabling consists of 22 AWG to 26 AWG cable, but this has not affect the slender the widespread popularity of jump line.
Now, the dispute is over.
TR - a few weeks ago, TIA technology committee
Approved the new ANSI/TIA - 42 vote
D cabling standards, allows the use of 28 AWG jumper, ISO/IEC are likely to follow later.
Therefore, we think this is a make you a good time to 'lean'.
Problems of electrical resistance equal to the dc resistance is essentially a measure of the conductor's ability to hinder the current flow of an indicator, with the increase with the increase of the length of the conductor.
It is also related to the size of the conductor -
The conductor size, the greater the dc resistance is smaller.
Therefore, slim 28 AWG jumper has larger resistance in nature.
Test twisted-pair cabling, we need to consider dc loop resistance, namely a line around the end of the wire of the total resistance.
Dc resistance affected by the conductor diameter and the total length -
Not only have the larger diameter smaller conductor dc resistance, and resistance is proportional to the length of the cable.
According to the IEEE standard, line of channel dc loop resistance should be less than (
Or equal to)
25 ohms (
And the permanent link dc loop resistance should be less than (
Or equal to)
What does this mean for slim jumper?
In order to ensure that in 25 Ω dc loop resistance channel within a limit range, new TIA 568.
D 28 AWG standard proposed to channel the length of the jump line will be limited to 15 meters.
Although the switch to the server for data center environment link, this is usually not a problem, but when the 28 AWG jumpers for remote power supply applications (
Whether now or in the future)
, they will generate more heat than larger specifications jump line, therefore, under such circumstances, should consider to avoid using large cables.
In fact, TIA and ISO/IEC have already have a project to update the remote power supply guidelines, in order to take into consideration of the 28 AWG cable is.
Do if than the dc circuit resistance limit, please be sure to use DSX CableAnalyzer ™ series copper certification tester to check all the lines.
If only a couple of lines did not pass the test, it may be due to the termination undesirable, rather than because of using the slender jump line.
But if you use the 28 AWG cable channel all the line has not been to pass the test, you seem to have been wrong too wide of the mark.
Click on the image, watching the DSX series tester teaching video learning more loss, need derating from the perspective of signal, insertion loss is considered to be more important performance parameters.
Loss of signal is signal along with any type of cable transmission of any length, the natural phenomena, and is similar to dc resistance, under the influence of conductor size and the total length.
Therefore, in addition to the dc resistance of a larger, 28 AWG jump line also has higher insertion loss due to the loss is directly related to the channel length, so using 28 AWG jumpers need to shorten the total length of channel.
The channel length is reduced to less than 100 meters (
The permanent link wiring by 90 meters and 10 meters of jump line)
Called derating, and different types of cable and application have derating factor, to adapt to the requirements of insertion loss.
Because of fever, for example, can cause insertion loss, so the cable derating coefficient under high temperature.
Due to the insertion loss increase, it is recommended that the 28 AWG jumper derating coefficient is 1.
95, in this way, the total length 100 meters channel will be reduced to 96 m -
90 meters of permanent link wiring and 6 meters jump line.
If you need to keep 10 meters long jump line, you will need to further shorten the channel length.
For example, the use of derating factor 1.
Calculating channel greater length (95
Must be less than 102 meters)
28 AWG jump line, use the 10 meters when total permanent link length should be 82.
5 meters (
The channel length for 92.
102 - meter -
95 derating factor X 10 meters)
Is calculated using the same 5 meters, if you use a larger recommend length is 15 meters 28 AWG line, it only supports the permanent link for about 73 meters (
The channel length of 88 meters)
Therefore, if the channel is longer than 6 meters 28 AWG jumper, and insertion loss test failure, is likely to need the normal length of 90 meters of permanent link shorten appropriately.
However, due to the fine cable main deployment in the data center area of the high density jump line, so the length of the link is often far lower than 90 meters, so for most users, derating is not a big problem.
In general, the industry consensus is that 28 AWG jump line (
To improve the air circulation and cable management)
The advantages of obvious more than disadvantages (
Channel length shortening)
And this is why the thread has been recognized by the industry standard.
If you have any questions or problems, you are welcome to contact us at any time