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T1-Distance

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samuri

Technical User
Feb 8, 2002
82
US
Can anyone tell me the max distance between a T1- smart jack and the csu/dsu?

Thanks in advance
 
You can get quite a bit of distance, especially if you use good cable and it is not routed past a buch of interfering stuff. Rememnber this is slow speed.
 
"quite a bit" still leaves me wondering. I would first consult the manual for the CSU/DSU and see if they have a recommended limit. I really haven't seen a published limit on that connection.

In my experience, I've run them 100-200 feet on Cat5, and in excess of 400 feet on DS1 cable (two pair, individually shielded). The troublesome part is how do you know when it starts to fail?

Often questions here are either "can" or "should". You probably CAN run Cat5e over 328 feet, I've done it at 100 mbs at almost 400 feet. But, you SHOULD only run the channel (fixed portion) 90 meters and then jumpers up to 100 meters total.

Maybe someone knows of a rule or guideline for this and can enlighten the group.

Good Luck! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
 
Does anyone know where I can get some pictures of T1 Smartjacks? jeff moss
jeffmoss26@adelphia.net
 
Hmm, anyplace there is a T1?

Seriously, I am finding more and more that the local telcos here are using PairGain products. I believe you could find some pictures on their website.

Good Luck! It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
 
is there a telco code for a smartjack? maybe that will help me look up info online. jeff moss
jeffmoss26@adelphia.net
 
Lots depend on the media being used and the CSU/DSU being used. Many CSU's have LBO's (Line Build Out) options. Most come default from the factory at 0-133 feet and increase from there. ADC Kentrox and Adtran's can go as far as 1,000 feet with good cable. Sheilded/stranded T-1 wire is often used in place of UTP for distances over 200 feet. Either way we have had good success at 700-800 foot ranges using LBO's on CSU and T-1 hardware. Daron and Bobg1 have good points on this subject and remember topped out you are only doing 1.54M. Let the CSU be responsible for repeater functions. Jerry Pannell
techs@sclb.com
 
3000' is the max length to the nearest repeater. Since other factors like quality/gauge of wire add up to loss, the easiest method of calculation is to measure the voltage of the T-1 at your CSU equipment with a volt-meter.

Voltage Cable length to repeater CSU setting
<1.68 >3000 CSU is too far
1.68 3000 15dB
2.03 2500 7.5dB
2.47 2000 7.5dB
3.05 1500 7.5dB
3.76 1000 0dB
4.51 500 0dB
>4.51 <500 0dB

Excerpt from Lucent Definity DS1/CEPT/ISDN PRI Reference manual 555-025-107. -CL
 
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